Midwest Native Seed Network’s missing restoration species survey provides a framework for action

Posted on August 24, 2026 by jmasonfpdwc

Authors: Andrea Kramer (Senior Director, Restoration Ecology), Ryan Lothian (Senior Manager of Conservation Impact), Chris Woolridge (Senior Manager of Seed Projects and Partnerships) and Owen Zaengle (Principal Web Applications Developer) – Chicago Botanic Garden

Left: Chris Woolridge and Dave Sollenberger assessing the flower morphs of a Lithospermum canescens railroad population in central IL under threat from autumn olive. Right: Hoary puccoon (L. canescens). Photos credit: Sarah Hollis, Chris Woolridge.

The Midwest Native Seed Network is a developing coalition of organizations and individuals working to increase the availability of genetically appropriate native seed across the region. Currently led by a steering committee of staff from Chicago Botanic Garden, US Fish and Wildlife Service, and The Xerces Society for Invertebrate Conservation, we are building connections and resources to develop more robust, diverse, and local native seed supply chains.

To begin understanding and addressing gaps in species and source availability, we conducted a region-wide electronic survey in 2025, targeting land managers to see which species are missing from their restorations and why. First, we gathered information from each respondent to understand their seed sourcing strategy, definition of ‘locally sourced material’, and which ecoregion(s), state(s), and counties they work in. We also asked about any successes they’ve had with difficult species. Respondents listed the top ten priority species they are unable to obtain or have trouble establishing, and why:

  1. Not commercially available
  2. Not commercially available from an appropriate source
  3. Not commercially available in sufficient quantity
  4. Cost prohibitive
  5. Cannot get established
  6. Other:

If a respondent had more than 10 priority species to share, they were encouraged to submit a spreadsheet separately. We received responses from 54 unique respondents across the region, with 534 unique species listed. While all states in the region had at least one respondent (Fig. 1), almost half of all respondents were from Illinois. The most stated limiting factors were: ‘Not commercially available’ (356, 67%) and ‘Not commercially available in sufficient quantity’ (346, 65%) (Fig. 2).

Summarized results can be viewed and filtered in an Overview, Species View, State View, and Limiting Factor View on the Missing Species Survey Dashboard HERE. In the Overview tab, viewers may filter survey results by a combination of species, state, and limiting factor.

Fig. 1: Number of survey respondents by state. We received responses from 54 individuals. *The MANY category represents survey respondents that reported working in multiple states. One worked in IL, IA, MI, MN, ND, SD, WI; the other worked in IN, MI, OH.

Fig. 2: Total frequencies for each limiting factor being listed in the survey. We received responses for 534 species.

The top 13 species listed at least 12 times across the region were:

  • Viola pedatifida – prairie violet (21)
  • Comandra umbellata – false toadflax (20)
  • Lithospermum canescens – hoary puccoon (19)
  • Pedicularis canadensis – wood betony (19)
  • Geum triflorum – prairie smoke (18)
  • Phlox pilosa – prairie phlox (14)
  • Asclepias purpurascens – purple milkweed (13)
  • Pulsatilla patens – eastern pasqueflower (13)
  • Calamagrostis canadensis – blue joint grass (12)
  • Ceanothus americanus – New Jersey tea (12)
  • Gentiana andrewsii – bottle gentian (12)
  • Lilium philadelphicum andinum – prairie lily (12)
  • Pediomelum esculentum – prairie turnip (12)

Species highlights:

Photos credit: Chris Woolridge
  • Comandra umbellata (false toadflax) – primarily listed as not commercially available and difficult to establish.
  • Lithospermum canescens (hoary puccoon) – primarily listed as not commercially available and not commercially available in sufficient quantity.
  • Pedicularis canadensis (wood betony) – primarily listed as not commercially available from an appropriate source and not commercially available in sufficient quantity.
  • Viola pedatifida (prairie violet) – primarily listed as not commercially available in sufficient quantity and cost prohibitive.

The top ‘missing species’ listed in the survey were the very conservative usual suspects. The average C-value for the top 13 species listed above is 8.6. Most of our seed user respondents come from ecological restoration, and the species they are having difficulty sourcing are difficult to grow and/or source due to life history traits and their conservatism. However, we also received a few unexpected submissions for aggressive, early successional natives, including: Alopecurus carolinianus (annual foxtail), Erigeron philadelphicus (Philadelphia fleabane), Hordeum jubatum (foxtail barley), Panicum capillare (witchgrass), and Solidago altissima (tall goldenrod).

These ‘weed’ species are at the opposite end of the C-value spectrum, and we initially questioned why they were submitted in this survey. We spoke to Jon Hawthorne, from the Indiana Department of Transportation, who submitted the species listed above, and he expressed his goals of creating a successional framework for roadside plantings. Jon is looking for seed of early successional, competitive species that can tolerate heavy growing season disturbance, invasives, and highly elevated nitrogen runoff. Due to the degraded and disturbed nature of these spaces, Jon has chosen to initially select for these more ruderal native plants with plans to increase the number of and frequency of conservative species in these spaces as they mature and stabilize. Although a small part of this survey’s findings, hearing about these ruderal species gaps for DOT plantings was enlightening. We hope the Network will facilitate conversations between various kinds of land managers and growers about different project goals and demands.

Overall, the results of this survey will help us collaborate with growers, land managers, and researchers within the Midwest Native Seed Network to:

  • Form priority species lists for information gathering and synthesis, to be hosted on a Native Seed and Restoration Knowledge Base
  • Identify bottlenecks limiting production, availability, affordability, and establishment of these ‘gap’ species and genera
  • Build a research strategy and framework, develop collaborative projects that will increase the availability and use of these species

We recognize that these survey results do not provide a comprehensive picture of species availability gaps for the Midwest. However, we do feel the results provide a good starting point and direction for the Network’s efforts towards improving native seed availability.

Find more information about the Midwest Native Seed Network: https://www.midwestseednetwork.org.

To keep up to date with the Network, please consider signing up for our email list: https://lp.constantcontactpages.com/sl/dCIlObM/MidwestNativeSeedNetwork

Find the Missing Species Survey Dashboard here: LINK

The Missing Species Survey Dashboard was built by Owen Zaengle, Chicago Botanic Garden. We’d like to extend a sincere thank you to everyone who took the time and effort to complete the survey and contribute their time and effort to the project, as well as everyone who contributed edits and thoughts to the survey structure and questions.

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Sericea Lespedeza Control – Summer Burning and Herbicide Treatments

Posted on August 20, 2026 by jmasonfpdwc

By: Barbara Sherwood and Julianne Mason, Forest Preserve District of Will County, IL

Key Takeaways

  • A late-August prescribed fire killed all mature sericea lespedeza (Lespedeza cuneata) plants where the fire burned with at least moderate intensity.
  • Herbiciding the base of sericea plants with a mixture of Triclopyr 4 herbicide in bark oil during early September killed 100% of treated mature plants while causing minimal collateral damage to neighboring native forbs.
  • One year after treatment, seedlings were present near previously occupied sericea locations, indicating that follow-up monitoring and treatment will be necessary to exhaust the soil seed bank.

Background

At one of our prairie preserves near Braidwood, Illinois, we have incorporated late-August prescribed burns into a rotating program of primarily dormant season burns. The summer burn timing is intended to benefit the Rattlesnake Master Borer Moth (Papaipema eryngii), an endangered insect in Illinois.  By late August, the larvae have tunneled belowground into the roots of rattlesnake master (Eryngium yuccifolium), where they are protected from fire. In contrast, dormant-season burns may consume eggs that have been deposited in the  duff layer. This vulnerability is shared by many prairie insects, both common and rare, reinforcing the importance of burning only portions of a site in any given year and rotating burn units over time.

Summer burn done on August 26, 2025, in a prairie restoration near Braidwood, IL.

Growing-season burns also have potential ecological drawbacks. Consequently, we limit these burns to areas where rare reptiles and amphibians are absent and burn relatively small units, minimizing the risk of direct mortality to species that may be active aboveground during the growing season.

Although an interesting topic, the potential benefits and drawbacks of growing season burns isn’t the point of this article.  After the growing season burn last year on August 26, 2025, our crew did a post-burn basal bark treatment to unwanted woodies in the burn unit.  This is a highly effective management technique which we strongly endorse – see here – but it’s also not the point of this article.

Mortality of invasive shrub after post-burn basal bark treatment.

Treatment Methods

Now we’re coming to the point of this article.  The unit burned in August 2025 is a 10-year old prairie restoration that has scattered sericea lespedeza (Lespedeza cuneata), a highly invasive perennial legume. While the crew was doing the post-burn herbicide treatment to woodies on September 2, 2025, they also “basal barked” or base sprayed several dozen mature sericea plants.  This involved using a backpack sprayer to treat the base of the sericea plants with 15% Triclopyr 4 herbicide mixed in bark oil. The lower two inches or so of the sericea were sprayed, both front side and back side, with the herbicide mixture. At the time of treatment, the sericea plants were just starting to flower.

Left: Sericea (Lespedeza cuneata) just before the summer burn and herbicide treatments in 2025. Right: Monitoring the effects of the treatments one year later (2026).

To evaluate treatment effectiveness, pin flags and GPS coordinates were used to mark about a dozen individuals in three treatment groups:

1) Sericea plants that received the prescribed burn only.

2) Sericea plants that received the prescribed burn followed by base spray herbicide treatment.

3) Sericea plants in an adjacent unburned area that received base spray herbicide treatment only. 

Fire intensity varied across the burn unit. Many sericea stems remained standing following the burn, exhibiting varying degrees of scorching from light to moderate. For each marked plant, the degree of scorching and whether green tissue remained one week after the fire were recorded.

The summer burn done in August 2025 burned through most of the unit, but fire intensity varied. The vegetation in some areas was fully consumed (left) but in other areas only the duff layer burned (right).

Results

One year after treatment, all plants that had received the base spray herbicide application were dead, regardless of whether they occurred in burned or unburned portions of the site. This represents 100% mortality among the treated plants.  An additional benefit of the base spray technique was the confined amount of overspray. Damage to adjacent native forbs was minimal and substantially less than would typically be expected from a foliar application of either triclopyr ester (T4) or triclopyr amine (3A).

Left: Sericea lespedeza before treatment. Right: Dead! No sericea re-growth one year after base spray herbicide treatment.

Prescribed fire alone also proved highly effective. Every mature sericea lespedeza plant exposed to at least moderate scorching was dead one year after the burn. The single surviving plant experienced only very light scorching and retained green foliage one week after the burn.

In a previous Grassland Restoration Network post, Jeff Horn (Illinois Department of Natural Resources) documented sericea lespedeza treatments that included summer prescribed burning. At his site, some sericea plants resprouted following fire. However, because summer burns can be patchy and vary considerably in intensity, tracking individual plants can help establish the relationship between burn coverage, fire intensity, and plant mortality.

At our site, all tracked sericea plants that experienced at least moderate scorching were dead at the one-year evaluation. These results suggest that where summer fire achieves moderate or greater intensity at the plant level, it can provide substantial control of mature sericea lespedeza. However, these observations are based on a single burn at one site and should be interpreted accordingly, as noted in the disclaimer at the end of this article. It will be valuable to determine whether these results are consistent across multiple sites and years, particularly under varying weather and fire conditions.

Left: Sericea lespedeza before the 2025 summer burn. Right: Same sericea plant viewed one week after the burn.
Left: Same sericea plant as above, note small amount of green foliage remaining after the 2025 summer burn. Right: Dead! No sericea re-growth one year after the burn (2026).

One year after the treatments, numerous small legume seedlings were present around many of the locations formerly occupied by mature sericea plants. Although these seedlings may be sericea, some may be sweet clover or native legumes and follow-up monitoring will be needed to verify species identifications. 

Left: Many small legume seedlings present in 2026 where mature sericea had been killed. Right: Rattlesnake master bloomed profusely in the year after the summer burn.

Management Implications

It will take continued monitoring and treatments to the next generation sericea plants to deplete the seedbank and reduce the invasive sericea population.  In the ongoing effort to control this invasive perennial, it’s helpful to know that both late-summer burning and base spraying with triclopyr 4 herbicide in bark oil are effective treatments. We intend to alternate these treatment methods on an annual basis as we continue to address the sericea at this preserve.

Both summer burn (left) and base spray herbicide treatments (right) were effective at killing mature sericea lespedeza, as evaluated one year after treatment.

Disclaimer: This was an impromptu field study, not a formal experiment.  Sample sizes were small and not replicated across multiple sites.  However, by marking treated individuals and tracking their fate, we can get useful information on treatment effectiveness. Our collective understanding is strengthened when we monitor diligently and share observations and results from across our various sites. Even informal field observations can contribute valuable information when considered alongside results from other practitioners and locations. 

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Are Two Sweeps Enough? Conversations with the Crew

Posted on August 13, 2026 by Clara Barton

By:

Clara Barton

Every summer, Nachusa’s field crew spends long days walking through prairie vegetation searching for birdsfoot trefoil.

Pictured left to right; Ryn Kreitz, Ocean Ramirez, Matt Molson, Dakota Lohman (photo credit: © Charles Larry)

At first glance, it sounds simple enough. Find the plant. Spray the plant. Move on.

But birdsfoot trefoil rarely cooperates.

Some plants flower early. Others wait until weeks later. Bright yellow blooms that seem impossible to miss during one visit may not have emerged yet during the first sweep. Meanwhile, vegetative plants hide among grasses and native wildflowers, blending into the surrounding prairie.

As Crew Lead Katie Jo explained:

“[Birdsfoot trefoil] starts [as a] non-flowering, very small indescript plant. When you know it, you know it, but it can be short, it can be tall, it can be as big as the vegetation around it, it can be hardly anything. A lot of the times it’s not flowering and then it is flowering [at seemingly] random times in the summer.”

Because birdsfoot trefoil does not all bloom at once, some of Nachusa’s worst infestations receive a second sweep later in the season. The return visit gives the crew another opportunity to catch plants that were missed most likely because they had not yet flowered during the first treatment.

We wanted to know whether our current treatment strategy was working as well as we thought it was. Are two sweeps enough to catch most birdsfoot trefoil plants, or are some sites needing more?

To find out, I established monitoring plots in three areas with known birdsfoot trefoil infestations: Wades Bottoms, Big Woods, and Leopolds Knob. Before treatment began, I counted every birdsfoot trefoil plant inside a series of one-square-meter plots. I then revisited those same plots after the first sweep and again after any follow-up treatments. The goal was not to measure the overall infestation at each site, but to evaluate how effective Nachusa’s current treatment strategy is at finding and treating birdsfoot trefoil over multiple visits. My question was simple: are two sweeps enough to catch most plants?

Wade’s Bottoms

Wades Bottoms generally received strong coverage during the first sweep. Most monitored plants were treated successfully, and overall infestation levels were lower than expected. In fact, Crew Lead Katie Jo noted that this season was noticeably different from previous years, saying, “It was the least amount of [birdsfoot trefoil she’s] ever found in it.”

Because crews were finding fewer plants than expected, the area was not selected for a second sweep. Decisions like this often involve balancing time and resources across the preserve. As Katie Jo explained, “I try and make the decision [based] on what our time [is] best worth spent doing when we’re fighting other weeds.”

While Wades Bottoms did not achieve complete control within the monitored plots, having a few remaining vegetative plants, the results were encouraging. Compared to previous years, infestation levels appeared substantially lower, suggesting that years of continued management and the use of preemergent treatments may be reducing the overall abundance of birdsfoot trefoil in the area. Katie Jo also noted that, from her perspective, Wades Bottoms “felt significantly better to me [with] less BFT than two prior summers that I’ve been spraying there.”

Big Woods

Big Woods presented a very different challenge.

Unlike the other monitoring areas, much of Big Woods received an initial tractor treatment rather than being treated entirely on foot. The decision was driven by the sheer volume of birdsfoot trefoil present. As Crew Lead Katie Jo recalled, the crew was encountering “mats and mats and mats of BFT” across portions of the unit.

Large tractor treatments allowed a great deal of ground to be covered quickly, but the site’s size and infestation density also made it one of the most difficult areas included in the study. Following the first treatment, many plants remained within the monitoring plots. A follow-up sweep improved results considerably, although a few plants still persisted.

The challenges at Big Woods were not unexpected. Crew members have long regarded it as one of Nachusa’s most persistent birdsfoot trefoil problem areas. As assistant crew leader Ocean explained, “Our unit Big Woods we know has had a large problem with BFT throughout its years, so we know that it’s one that we have to watch carefully.”

The site’s dense vegetation and heavy infestation likely contributed to some plants being overlooked. While tractor treatments remain a valuable tool for rapidly treating large concentrations of birdsfoot trefoil, the monitoring results suggest that they are most effective when paired with follow-up sweeps on foot. Big Woods also provided the strongest evidence that particularly severe infestations may occasionally benefit from a third visit, especially when the crew is finding quite a few plants during the second sweep.

Leopold’s Knob

Leopolds Knob showed the best overall treatment effectiveness.

By the end of the treatment process, every monitored plant had been captured, and follow-up visits revealed very few issues.

One reason may have been visibility. Compared to the other sites, vegetation at Leopolds Knob was generally shorter, making birdsfoot trefoil easier to detect.

Crew member Ryn noted similar differences between the sites:

“Leopold’s is much more open… [birdsfoot trefoil] is much more visual, especially when you have those yellow flowers. With Big Woods you have a much denser stand of grasses and different mixes of plants that could be more challenging”

Whatever the reason, Leopolds Knob provided the strongest evidence that two sweeps can be highly effective when plants are easy to detect and crews are able to thoroughly cover an area.

Slide to watch the birdsfoot trefoil disappear after two sweeps

Blog post on what the crew sprays birdsfoot trefoil with: Comparison of Transline and Milestone-Based Treatment for Birdsfoot Trefoil Control | grassland restoration network

Why do Second Sweeps Work?

One pattern emerged across all three monitored sites.

The plants most likely to survive the first sweep often weren’t flowering plants at all. Instead, they were vegetative individuals tucked among surrounding vegetation. Without bright yellow flowers announcing their presence, these plants can be surprisingly difficult to find.

Crew member Matt wasn’t surprised by this result:

“Bird’s-foot trefoil … flowers continuously over the summer. [The flowers] [are] useful for helping us find the plant. The yellow flower is very easy to see. But it’s not really a guarantee when you first go through an area if the plant is going to be flowering or not. You can still find the vegetative plant, and that’s not too hard to do, but this is something also that I think helps with second sweeps. If it wasn’t flowering the first time, it should be [by] the second.”

This observation helps explain why return visits are so valuable. A plant that blended into surrounding vegetation during the first sweep may be flowering by the time a crew revisits the area.

Vegetation itself also becomes a challenge as summer progresses. As crew member Sam explained:

“The surrounding cover characteristics change too. As you get kind of into the warm season, those warm season grasses really sprout up, really dense up, which just makes it tricky to see something like bird’s-foot trefoil, which is primarily lower to the ground.”

Together, these factors help explain why a single treatment often isn’t enough and why repeat visits remain an important part of Nachusa’s management strategy.

Blog Post about repeat visits: Make repeat visits to reduce weed occurrences | grassland restoration network

More Than Just Finding a Weed

The results were encouraging. Across the sites I monitored, Nachusa’s two-sweep strategy captured the vast majority of birdsfoot trefoil plants. The approach appears to be working, particularly in areas treated on foot by the field crew. At the same time, the study reinforced a broader lesson about prairie conservation. Removing invasive species is not simply a matter of finding plants and spraying them. Effective management requires planning, observation, monitoring, and often multiple visits to the same site.

As Sam put it:

“People think that it’s just letting nature go and it’s not killing anything, not messing with anything, kind of just leaving it untouched. And in a sense that’s true, but there is a lot of discipline and directed management involved.”

That management is part of something much larger than birdsfoot trefoil control alone.

As Katie Jo explained:

“When we’re doing our weed sweeps, what we’re doing in the grand scheme of things is protecting the prairie.”

The findings from this project suggest that two sweeps are often enough to catch the majority of birdsfoot trefoil plants, though exceptionally heavy infestations may occasionally warrant a third visit. More importantly, the project highlights the value of persistence.

Assistant Crew Lead Ocean reflected on that long-term perspective:

“The work here is not any one person’s responsibility and it’s not any one season’s responsibility. Each season builds upon the last and I think that’s really important to remember in any kind of conservation work that you do because sometimes you look at a space and you think, ‘How on earth is this gonna get done? How on earth are we gonna fix this?’ But you have to remember that it’s not just you, it’s everyone you’re working with, everyone’s knowledge that you’re using, and the people who are gonna come after you and do the same kind of work that you’re doing. So even though if you’re walking a line and you’re thinking, ‘Man, I don’t know that I’m gonna ever see the results of this,’ you know that one day someone will. And to me, that’s really important.”

Like many aspects of prairie restoration, birdsfoot trefoil management is not about achieving perfection in a single season. It is about making steady progress year after year, building on the work of those who came before and leaving the prairie a little better than when you found it.

Left to right: Clara Barton, Ryn Kreitz, Matt Molson, Katie Jo Jackson, Dakota Lohman, Tess Birsa, Sam Odell, Emily Holthrop and Ocean Ramirez (photo credit: © Dee Hudson)

Special Thanks to the crew!

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Comparison of Transline and Milestone-Based Treatment for Birdsfoot Trefoil Control

Posted on August 6, 2026 by Clara Barton
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Clara Barton

Jump to Quick Summary of Results
Birdsfoot trefoil (Lotus corniculatus)

Introduction

Birdsfoot trefoil (Lotus corniculatus) is a persistent invasive legume at Nachusa Grasslands.This plant can form dense mats that smother and outcompete native plants. Current management of this weed involves herbicide treatments that aim to kill the plants fully to the roots and remain in the soil to prevent seeds from establishing. This weed is one of our main targets during weed season. Because of its strong establishment at Nachusa Grasslands we have also used pre-emergent treatments to work towards getting rid of this plant. Here is a post that explains that: Weed management | grassland restoration network.  For members of the Fabaceae family, such as birdsfoot trefoil, sweetclover, and crown vetch, chemicals such as aminopyralid, clopyralid, and 2,4-D are often recommended for management. At Nachusa, the crew uses a mixture of Milestone (aminopyralid), Garlon 3A (triclopyr), and Methylated Seed Oil (MSO) during the heaviest part of the weed season to treat multiple weeds. This mixture covers a larger range or broadleaf plants. For this experiment we tested the crew’s current mixture against Transline (clopyralid) and a lower percentage of Milestone (aminopyralid) without the addition of Garlon.

Dead spots caused by the Milestone and Garlon 3A mixture
TreatmentMixture
AMilestone 0.5% (v/v)
Garlon 3A 1% (v/v)
MSO 0.5% (v/s)
BTransline 1% (v/v)
MSO 0.5% (v/s)
CMilestone 0.075% (v/v)*
MSO 0.5% (v/s)

*Using 0.1 ounces per gallon

Observations

In late June the plants were treated using backpack sprayers. Each plant was labeled with a flag marking which treatment was received. Before pictures were taken, and plants were checked every week following. Initially, the plants in treatment groups with Transline (treatment B) and diluted Milestone (treatment C) showed slower symptom development than those in that treatment group with the crew’s mixture (treatment A). In group A the plants started browning a few days after being treated and a noticeable kill zone surrounding the plants was observed. By early July plants in treatment B were noticeably curled and wilted but continued to produce seed at normal rates unlike plants in groups A and C which still had some plants forming seed pods present, but in lower numbers than group B. By the end of July it was clear that all plants were dead, however the plants exposed to milestone did die more rapidly. Of the two treatments using Milestone the one containing Garlon (treatment A) did have a more rapid impact on the plants than the one without (treatment C), but both treatments were effective at killing the plants. Treatment C also showed less impact on surrounding plants than treatment A.

Seed production on plant treated with Transline

Discussion

These treatments were applied later in the season (end of June), treatment for this plant at Nachusa usually begins at the end of May. The birdsfoot trefoil plants treated were fully in bloom when sprayed and gearing up to produce seeds which impacted the results of this study. At Nachusa we treat birdsfoot trefoil with both Transline or Milestone mixtures. Both herbicides have worked for us historically. However, this experiment suggests that when spraying later in the season it might be beneficial to utilize a faster acting herbicide to reduce seed production.

Aminopyralid (Milestone) and clopyralid (Transline) are both effective in treating Birdsfoot trefoil, but the aminopyralid (Milestone) is often found to have a stronger biological effect (higher activity), than clopyralid (Transline) according to this study: A Comparative Analysis of Aminopyralid and Clopyralid Efficacy in Broadleaf Weed Management. This study conducted by BenchChem found the following;

 “Both aminopyralid and clopyralid are effective herbicides for the management of a wide range of broadleaf weeds. However, experimental data consistently demonstrates that aminopyralid offers a significant advantage in its ability to provide high levels of control at lower application”

This concept may also add some context as to why the plants treated with Milestone showed symptoms so much faster than those treated with Transline. It also potentially helps to explain why plants treated with Transline ended up producing more seed then those treated with Milestone. In terms of late season applications, Milestone performed better for our objective by killing the plants before they could fully complete seed production.

Birdsfoot Trefoil both with flowers and seeds

The product labels and fact sheets suggest that Milestone has a strongest residual activity (~6-12 months) compared with Transline (~2-6 months) and Garlon 3a (~2 months). This suggests that when battling a large build up of seed in the soil using milestone might be wiser given its long-term residual activity. In this study we analyzed top-kill and seed production only with visual observations. A more in depth expansion of this study might observe these plant populations over more time to better understand how the residual effects of these herbicides are impacting the rhizomes and the seeds in the soil as well as any regrowth from established plants.

The data from this study suggest that the choice of herbicide for treating birdsfoot trefoil should be based on timing. Treatment C (milestone) acts more slowly compared to treatment A (Milestone and Garlon), it is still effective in killing birdsfoot trefoil plants. It may be best suited for early-season applications when plants are still in the growing stage (May-June). When preventing seed production becomes more important adding in the Garlon 3A might be the solution. Here the crew often does two sweeps of areas with particularly bad infestations of birdsfoot trefoil. I can see a reasonable way to apply these findings being having them complete their first sweep with the concentration of milestone from treatment C and following up later with the Garlon 3A and higher Milestone concentration mixture.

Conclusion

This study found that

  • Transline = most selective of three treatments, slowest activity, late season spraying didn’t prevent seed production.
  • Milestone + Garlon = fastest control, greatest non-target effects.
  • Lower-rate Milestone = less selective than the Transline, slower activity than the Milestone with Garlon, prevented seed production better than the transline treatment.

Management of this weed will continue as is for the remainder of this current season, however next year it may be worth evaluating the herbicides and concentrations we are using. As I stated above I will make a recommendation for the crew to decrease the milestone percentage, at least at the beginning of weed season. There are many reasons why the crew might opt to keep the Garlon addition in this mixture. It increases the spectrum for broadleaf weeds they can treat with the same mixture preventing them from frequent remixing of chemical or having to keep more equipment so they could switch chemicals in the field. For this reason, I understand they will probably continue to use this broader coverage mixture. Dropping the Milestone from 0.5% to 0.1 oz per gallon should still result in effective top-kill of birdsfoot trefoil plants. One of the benefits of using Milestone over Transline is its strong effectiveness in low concentrations. Every birdsfoot trefoil seed prevented today is one less plant to battle tomorrow, knowing that our treatments are working is crucial in the continued management of our wonderful prairies.

Sources for this post

“Milestone Fact Sheet.” n.d. Accessed August 5, 2026. https://forages.tamu.edu/wp-content/uploads/sites/26/legacy-files/PDF/milestone.pdf.

A Comparative Analysis of Aminopyralid and Clopyralid Efficacy in Broadleaf Weed Management. n.d. https://pdf.benchchem.com/1667/A_Comparative_Analysis_of_Aminopyralid_and_Clopyralid_Efficacy_in_Broadleaf_Weed_Management.pdf.

 “Kill Birdsfoot Trefoil in My Yard without Killing the Grass. Product Recommendation Please – Ask Extension.” n.d. Accessed July 31, 2026. https://ask.extension.org/kb/faq.php?id=838569.

Maroso, Rita Poles, Cerci Maria Carneiro, Simone Meredith Scheffer-Basso, and Daniela Favero. 2009. “Morphological and Anatomical Aspects of Birdsfoot Trefoil and Big Trefoil.” Revista Brasileira de Zootecnia 38: 1663–67. https://doi.org/https://doi.org/10.1590/S1516-35982009000900004.

Taylor, T. H., W. C. Templeton Jr., and J. W. Wyles. 1973. “Management Effects on Persistence and Productivity of Birdsfoot Trefoil (Lotus Corniculatus L.).” Agronomy Journal 65 (4): 646–48. https://doi.org/10.2134/agronj1973.00021962006500040035x.

“Transline® Herbicide.” n.d. Accessed August 5, 2026. https://www.corteva.com/us/products-and-solutions/land-management/transline.html.

“What You Should Know about Garlon® 3A Herbicide.” n.d. Accessed August 5, 2026. https://www.arborchem.com/images/label-sds/qa_Dow_Garlon3A.pdf.

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Comparing Herbicide Treatments for Bouncing Bet in a Grassland Restoration

Posted on July 30, 2026 by Clara Barton
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Written by: Clara Barton

Surfactant proves vital in diminishing populations of bouncing bet. Both Crossbow and Telar XP paired with surfactants show promising short-term control, though long-term effects on rhizome survival are still unknown.

Background

Bouncing bet (Saponaria officinalis), also known as soapwort, is a perennial forb introduced from Europe that is considered invasive throughout many parts of North America. This weed can form dense colonies through both seed production and spreading rhizomes, allowing infestations to persist and expand over time. The plant is characterized by smooth, waxy leaves and stems that contain saponins, compounds historically used in soap production. Its waxy leaf surface may reduce herbicide uptake and therefore limit treatment effectiveness when herbicides are applied without an effective adjuvant.

Bouncing bet (Saponaria officinalis)

Despite its aggressive growth habit, relatively little research is available regarding optimal management of bouncing bet. Existing management recommendations frequently suggest chlorsulfuron and other broadleaf herbicides for bouncing bet control. To evaluate treatment options commonly used by restoration practitioners, this study compared Telar XP (chlorsulfuron) and Crossbow (2,4-D + triclopyr). Surfactants are commonly recommended to improve herbicide absorption given the waxy nature of this plant’s leaves. Control is generally expected to require multiple years of treatment due to the species’ extensive rhizome system.

At Nachusa Grasslands, bouncing bet has never been one of our highest-priority invasive species because infestations remain relatively small. As a result, technicians have typically treated it with whatever broadleaf herbicide was available at the time. However, as part of our effort to stay ahead of emerging invasions, we wanted to determine which treatment option was actually the most effective.

Methods

The experiment was conducted on an established bouncing bet infestation located within the Visitors Center Prairie. The patch of bouncing bet present at this site was divided into three sections which received different herbicide treatments. Having these treatments so close to each other made comparing and contrasting the impacts easier to observe.

Bouncing Bet Patch pretreatment

Three herbicide treatments were evaluated:

Treatment Mixture
1Telar XP mixed at 2 grams of product per gallon of water, plus FS Talent (non-ionic surfactant)
2Telar XP mixed at 2 grams of product per gallon of water
32% Crossbow (v/v) plus methylated seed oil (MSO)

Having the Telar XP without the surfactant (treatment 2) was done to evaluate the importance of using a surfactant when it comes to treating this plant. The site was revisited regularly and documented with notes and photographs following treatment.

Summary of Observations

During the first week after treatment, Crossbow produced the fastest response, causing noticeable yellowing and damage. Telar XP alone produced little visible change, while Telar XP plus surfactant caused mild wilting.

By the second week, Crossbow-treated plants showed extensive yellowing and twisting. Plants treated with Telar XP alone developed reddish coloration and continued producing seed, while Telar XP plus surfactant caused much greater browning and stress.

After three weeks, both Crossbow and Telar XP plus surfactant appeared to cause substantial mortality. In contrast, many plants treated with Telar XP alone remained alive and still appeared capable of producing seed.

Plants three weeks post treatment:

Telar XP plus FS Talent surfactant treated plants
Telar XP treated plants
Crossbow plus MSO treated plants

Results

While Crossbow produced a more rapid visible response than Telar XP, speed of symptom development should not be interpreted as evidence of superior long-term control. Bouncing bet spreads through underground rhizomes, and plants that regrow from those structures can be especially persistent. Natto and Friedman (2025) found that rhizome-derived plants survived at higher rates than seed-derived plants, suggesting that long-term control depends on suppressing belowground growth as well as visible stems.

Survival differences between rhizome-derived and seed-derived Saponaria officinalis plants reported by Natto and Friedman (2025).

Telar XP (chlorsulfuron) is specifically recommended for bouncing bet management on the label and provides residual activity that may help reduce future populations. However, field observations from this study suggest that Telar XP alone may provide inadequate control without the addition of a surfactant. Based on the available evidence, both Crossbow and Telar XP plus surfactant appear capable of providing effective control, but Telar XP may have greater potential for long-term suppression due to its residual activity and documented use against bouncing bet. Additional monitoring over multiple growing seasons would be necessary to determine whether the rapid initial control observed with Crossbow translates into lower rates of resprouting and reinfestation.

Discussion and Conclusions

The results suggest that adding a surfactant was an important factor in improving Telar’s effectiveness. Bouncing bet’s waxy leaves makes it harder for herbicides to stick to and enter the plant. This likely explains why the Telar XP plus surfactant treatment performed much better than Telar XP alone. Although chlorsulfuron is commonly recommended for bouncing bet control, our observations indicate that it may be less effective when applied without a surfactant. In practical terms, the success of Telar XP treatments may depend not only on the herbicide itself, but also on using an adjuvant that helps the herbicide penetrate the plant.

Crossbow consistently produced the fastest and most dramatic visible symptoms. The yellowing and stem twisting observed in treated plants are characteristic responses to auxinic herbicides such as 2,4-D and triclopyr, the active ingredients in Crossbow. While these symptoms developed rapidly and caused substantial aboveground injury, visible top-kill does not necessarily indicate superior long-term control. As mentioned above, bouncing bet spreads through persistent rhizomes, making control of belowground structures important for lasting suppression. In contrast to the Crossbow, Telar XP is a systemic herbicide that translocates throughout the plant and may move into underground tissues before visible symptoms develop. This slower response may explain why Telar XP appeared less dramatic initially despite its potential to suppress rhizome-driven regrowth. Additional monitoring will be necessary to determine whether this translates into improved long-term control.

Another interesting observation was the condition of the plants’ flowering and seed-producing structures. By the end of the study, the Telar XP plants without surfactant still had noticeable green tissue around developing seed heads, while those treated with Crossbow or Telar XP plus surfactant were almost completely brown and dried down. Although we did not measure seed production or viability, this difference suggests that plants receiving Telar XP alone may have continued directing resources toward reproduction longer than plants in the other treatments. This would be an interesting question to explore in future monitoring.

While this was a relatively small field trial, it provided valuable insights into how bouncing bet responds to commonly used herbicide treatments. The study was conducted on a single infestation and relied primarily on visual assessments during the first three weeks following treatment, so additional monitoring will be needed to evaluate rhizome survival, regrowth, and long-term population decline. Even so, the results clearly highlighted differences among treatments and identified several areas for future investigation.

Key Takeaways

  • Telar XP performed poorly without a surfactant.
  • Adding a surfactant greatly improved Telar’s effectiveness.
  • Crossbow produced the fastest visible response.
  • Both Crossbow and Telar XP plus surfactant provided strong short-term control.
  • Additional monitoring will determine which treatment gives the best long-term suppression of bouncing bet.

Notes

Additional monitoring in 2027 is recommended to evaluate regrowth, rhizome survival, and reinfestation. Long-term observations will ultimately determine whether the rapid response observed with Crossbow or the slower systemic activity of Telar XP plus surfactant provides more durable control.

Bibliography

“Bouncing-Bet // Mizzou WeedID.” https://weedid.missouri.edu/weedinfo.cfm?weed_id=251.

 Corteva Agriscience. Crossbow® specialty herbicide label. EPA-registered product label.

Envu Environmental Science. (2020). Telar® XP Herbicide label (EPA Reg. No. 432-1561). U.S. Environmental Protection Agency. https://www3.epa.gov/pesticides/chem_search/ppls/000432-01561-20200320.pdf

“Jefferson County Invasive Species Management Program. Bouncing Bet Information Sheet.” n.d. .https://www.jeffco.us/DocumentCenter/View/1183/Information-Sheet-on-Bouncingbet-PDF.

Natto, Alyson C. Van, and Jannice Friedman. “Seasonal Life-History Trade-Offs Differ between Plants Derived from Seed versus Rhizomes in Saponaria Officinalis.” Preprint, bioRxiv, October 29, 2025. https://doi.org/10.1101/2025.10.28.685121.

“Range and Pasture Recommendations for Bouncingbet.” n.d. https://www.weld.gov/files/sharedassets/public/v/1/departments/public-works/documents/bouncing-bet-identification-and-management-final.pdf.

“Saponaria Officinalis | UMass Amherst Landscape, Nursery & Urban Forestry Program.” https://extension.umass.edu/weed-herbarium/weeds/saponaria-officinalis/index.html.

“Saponaria Officinalis Profile – California Invasive Plant Council.” https://www.cal-ipc.org/plants/profile/saponaria-officinalis-profile/.

“USDA Natural Resources Conservation Service. Bouncing Bet. Illinois Grazing Manual Fact Sheet, 2006.” n.d. https://www.nrcs.usda.gov/sites/default/files/2022-12/BouncingBet.pdf.

“USDA Plants Database Plant Profile Characteristics.” https://plants.sc.egov.usda.gov/plant-profile/SAOF4/characteristics.

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Make repeat visits to reduce weed occurrences

Posted on July 23, 2026 by Grassland Restoration Network blog

By Bill Kleiman

How many visits does it take to get an invasive weed occurrence to zero?

Lespedeza daurica, Asian bushclover. In its typical sprawling stance, with Jay and Leah hanging at the Nachusa picnic table

For years I have stated this answer of how many visits do we need to make to a weed occurrence as thus:

Visit a problem area once a year and the weeds numbers continue about the same, perhaps increasing and perhaps decreasing.

Visit twice a year to treat weeds and the weed numbers likely decrease by a modest amount. Do this annually for years and maybe you get success.

Visit three times a year and that year’s weed numbers decrease a lot, perhaps nearing zero adults surviving. This does not mean the seed bank is to zero, but that the year’s emerged adult plants are near zero.

What follows is an actual example of this idea.

On June 8, 2025 I went to a half acre prairie planting we did years back at our Meiners unit, in a dry upland corner with sandy soils. I looked carefully for Asian bushclover. The scientific name is Lespedeza daurica.

Asian bushclover, we call it ABC, is a low sprawling invasive bushclover. This is not Lespedeza cuneata, which most know as Sericea lespedeza, a weed which stands tall and proud while taking over all your beloved habitat. Both these bushclovers are very invasive, but ABC sprawls.

So on June 8, 2025, I found ten plants. I treated them with basal bark Garlon 4 from a squirt bottle because that is what I had with me. This weed emerges later in the season, and I think the first week of June was too early for this plant, which is why I found only ten plants. But I sprayed these ten.

Five weeks later,on July 12, 2025, I return to this same half acre and find 32 plants, which are mostly small. All the plants I treated in June with garlon 4 were dead. I had marked them with flagging tape so I knew it was them. On this July visit I happen to have a squirt bottle of imazapic and I spray the Lespedeza with it. What the heck, maybe imazapic works too. That I find 32 plants makes sense as mid-July is when ABC is big enough to be seen. All 32 are sprayed.

I return a third time, four and a half weeks later, on August 2, 2025. This is the same half acre of habitat. The same person is carefully searching. How many will I find? The same number? Less? More?

L daurica in seed

Well, on August 2 I find 29 ABC in about 4 patches with several each. I find the imazapic sprayed on my last visit did smoke them and every other plant in a little circle around the target Lespedeza is dead too. No surprise there. That is what imazapic does. I remember feeling dismayed that I found 29 plants because I think it means I missed 29 plants on my July visit. Ugh!

My final visit of 2025 is 9 weeks later on October 12, 2025. How many plants will I find?

I find only 3 plants with two next to each other, and a single.

So in summary, I made four visits and treated just about all of that year’s plants. And we could argue that my first visit was too early for this weed. So perhaps three visits would have had me find essentially all the plants.

But….I write this a year later on July 20, 2026. Clara and I found 31 plants today on this half acre, which is typical for this seed bank in this place. Weed work is a long game. Most of these 31 were likely just seeds, or little plants last year and now they are big enough to find. But worse, we found three big plants in one patch that were just off the half acre into the adjacent big prairie planting. I think those plants were missed in 2025. Double ugh!

Weed management is a long game. I have been searching this half acre for 19 years, since we first realized a local native plant nursery sold us this invasive Lespedeza. The nursery was apparently wild harvesting it from a site in the region. The problem with a plant nursery wild harvesting is that they send their workers to a site, workers who may not know what they are picking. They were not in a garden picking plants, but in a big area making botanical decisions. They bring back bags of seed that looks like the right seed, but it ain’t. What a bummer. Here is a blog post about that incident: https://grasslandrestorationnetwork.org/2021/09/09/beware-what-seed-you-buy/

And here is a link about the other Lespedeza, sericea lespedeza: https://grasslandrestorationnetwork.org/2025/10/23/control-of-lespedeza-cuneata/

And finally a link to a post describing various Lespedeza with a quiz: Lespedeza: friend and foe | grassland restoration network

So in summary, annually make two to three visits a year to your weed occurrences and you can expect success in the long run.

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Nachusa Grasslands Invasive Plant Monitoring Technician

Posted on July 9, 2026 by Grassland Restoration Network blog

By Clara Barton

Hello, my name is Clara Barton, I am the new Invasive Plant Monitoring Technician for Nachusa Grasslands. I recently received my master’s degree in ecology with a dissertation focused on studying the spatial biodiversity of grasslands. I worked as a seasonal restoration technician on the crew here at Nachusa in 2023 and 2024. Before that I was a restoration technician intern for the Missouri Botanical Garden’s Litzinger Road Ecology Center. Through my work, education, and research experiences, grasslands have become a cornerstone of my life. Spending time in prairies has taught me so much and given me a great appreciation for the amount of work required to maintain these absolutely gorgeous ecosystems.  Having a background in research and restoration has set me up well for this new position at Nachusa.

Clara Barton in the field

As the Invasive Plant Monitoring Technician my job is to run experiments to evaluate the methods we are using to manage invasive plant species at Nachusa Grasslands. I will be looking into many weeds including Honeysuckle (Lonicera maackii), Birdsfoot trefoil (Lotus corniculatus), yellow and white sweet clover (Melilotus officianalis, Melilotus alba), Sericea lespedeza (Lespedeza cuneata), and more. I will be focused on which herbicides are effective, mowing practices and timing, and if treated plants are still producing seeds.

Clara Barton excitedly conducting research on plants

The goal of these experiments is to make sure the measures we are taking to control an invasive species are working, as well as finding out if there are any treatments that would be more effective. I intend to make blog posts here about each experiment I conduct. Sharing what I learn here will hopefully benefit many other restorations that may be struggling with the same invasives.

Some of the questions I am currently working on right now include:

  1. What herbicide works best for Butter and eggs (Linaria vulgaris)
  2. Do mowed sweet clover stems resprout?
  3. Do mowed sweet clovers still produce seed?
  4. At what stage in seed development does Wild parsnip need to be hauled off after spading?
  5. What herbicide is best for treating bouncing bet (Saponaria officianalis) and how much surfactant is effective?
  6. What works better for Crown Vetch? Transline or Milestone?
  7. What herbicide is most effective for foliar treating honeysuckle resprouts?
  8. Is the Carpet wick effective at killing unwanted woody plants?
Experiment site for BFT study

I work together with Bill to come up with the questions that need answering to best help us with our work. If you have any questions about invasive plant management, feel free to put them in the comments.  We are always looking for more questions to investigate to help with the greater effort of restoration.

I look forward to sharing what I find!

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Pest shields for ticks, chiggers and such

Posted on July 6, 2026 by Grassland Restoration Network blog

By Bill Kleiman

The black flies of the Simuliidea emerged this week and congregate in the woods, especially areas with low wind. They will be a nuisance for a few weeks. And ticks are occasional. Mosquitos will be here soon. I thought I would share a few tips to deal with pests.

The bug net worked very well today. I forgot I had it on and could do all I wanted in the woods. The little pouch it comes in I hang from a carabiner off my pack or belt loop. The insect shield means it was dipped in permethrin pesticide at the factory, but I am not sure that was needed.

Permethin for your clothes, and Picaridin repellent for your skin

Permethin on the left by Sawyer, $19, is a pesticide you spray on clothing to ward off ticks and chiggers. Permethin is a synthetic version of a natural pesticide found in chrysanthemums. I see a one gallon of permethin for clothing by Insect Guard for $58.

On the right is Picaridin, which is what you put on your skin for mosquitos and such. It is not an insecticide but an effective insect repellent. Picaridin is nice in that it does not stink like DEET, nor does it melt or discolor plastic items like sunglasses and clothing. It is a lotion or spray for your skin. It works well. DEET is also a repellent, not an insecticide.

Treating all the clothing you wear in the field with permethrin is your best defense against tick diseases, bar none! Socks, hats, shirts, pants, boots. Permethin is expensive but worth it.

To treat clothes with permethrin I lay out my clothes to treat and wear a glove while spraying. You don’t want the water based solvent on your skin. I don’t know what is in that solvent but don’t get it on your skin.

You do a heavy spray on the clothes and let them dry for several hours and then they can be worn safely. This will repel ticks and chiggers and lasts for maybe a half dozen washings. I spray mine maybe twice a season. I lay items like socks, hat, on top of bigger items like pants or shirts so I don’t waste the expensive spray.

You can also send clothing items to a company, Insect Sheild, and they will dip them in a vat of permethrin and this apparently works well. I have heard from folks who did this and thought it worked great.

The permethin that is sprayed on livestock is cheaper, but it is an oil-based mix that you don’t want on your clothing.

On the right is a tick & chigger gator. It has permethrin on it too. I rarely wear these as we don’t have many ticks or chiggers at Nachusa, and they are too tight on my calves. There are other versions out that that are more of a snap around gator with permethin in it. You can tuck your pants in your socks, which I do at times, but the seeds stick to my socks.

Don’t let the pests keep you inside.

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Carpet Roller Wick to attempt to control brush

Posted on June 25, 2026 by Grassland Restoration Network blog

By Bill Kleiman, Nachusa Grasslands Director w The Nature Conservancy

Above, 17 days after a carpet roller herbicide wick drove over cottonwood saplings.

This is a Grassworks 22 foot wide carpet wick. A carpet on a long spool is soaked with glyphosate and it slowly spins as you drive through a brush thicket. Hopefully, you get enough herbicide on the brush to kill some of it, and you damage modest numbers of the good plants trying to grow under the brush.

Spoiler alert: We see modest success using this tool.

In its folded up travel position.

The carpet roller wick is soaked with glyphosate and spins slowly such that as you drive forward you are getting more herbicide on the foliage of the brush.

The carpet is spun with the little hydraulic motor spinning a rubber belt below the gray shield that turns the carpet roller.

In the cab of the tractor is a wired switch to start these electric herbicide pumps which squirt the glyphosate solution onto the carpet for a few seconds. Then about 20 seconds later you give another squirt of herbicide on the roller. You want the roller wet enough that it drips a little, but not a lot.

Results of a carpet wick on brush follows:

June 17, 2026 photo of a large patch of cottonwood saplings treated with a carpet roller wick two weeks before on June 2 and June 3, 2026. I used 33% glyphosate, 3% imazapic (Journey), and 10% LI700 Non ionic surfactant, and choice weather master water conditioner.

I wicked this patch two days in a row because the first day I did not use much surfactant in the mix. I think the best mix would be thick, like pancake batter, so that the roller could apply more herbicide and drip less. But the surfactant at ten percent still seemed to leave the solution looking watery. If you have used these before let us know how it went for you.

You can see the browned out cottonwood saplings which are about five foot tall. Some are alive. Maybe the browned out cotonwoods will still be alive next spring. We tagged some of the brown ones with tree paint to see how they fair next spring.

Above is that opening photo again after 17 days. Lots of brown cottonwoods now. If a bunch of those are dead I would call it a success. If they are just browned out and will recover later then not so much. We marked some individuals that look dead and will check on them this fall or next spring to see if they died. Applying blue tree marking paint is a good way to tag them. Flagging tape blows off.

A different unit. Above is the June 3 carpet wick work results on June 17, 2026. This is the Fen unit aspen clone. It was 10 foot tall! I had to run the wick at it full height so the stems would not break the wick. The results were some browned out, but I think the plants were too tall and robust to be heeled by a bit of glyphosate. We will brush mow the patch this winter, burn the unit again, and perhaps try the wick again.

For the wick to work you want the brush to be above the prairie, but not too tall. You don’t want big woody stems in there that wreak havoc on the tractor and wick. I plan to keep bringing this tool out to see what it can do.

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Shrub encroachment and fire

Posted on June 18, 2026 by Grassland Restoration Network blog

By Bill Kleiman

Konza Prairie w 4 year fire return interval on left, annual fire on right.

We recently heard from Emily Wedel who worked on her doctorate at Konza Biological Station, looking at shrub encroachment in seldom and frequently burned units. Konza has been studying and pondering the shrubs which have established on their plots that have had infrequent fire. Emily showed us the photo above where the infrequently burned unit was full of top killed shrub stems, shrubs that would all re-sprout come spring. On the other side of the fire break was an annually burned prairie that had no shrubs.

Emily also showed us maps of shrub encroachment where a 20-year fire return interval looks to have the same heavy shrub encroachment as the 4-year fire return interval. To me this suggests that the fire return interval should be one, two or three years. The unit with annual fire had essentially no shrubs even though just across a mowed fire break was a 20-year fire unit full of shrubs.

Emily shared this too. “I attach a paper from Konza where they reversed the fire treatments after 22 years. The infrequently burned watershed became annually burned and vis versa. Figure 3 has some good photos of the areas before and after the reversals. Burning every year opened up the canopy and increased grass biomass, so fire carried through, but the shrubs were still there at shorter heights.  [this paper has a fire wall and it is technical] https://url.us.m.mimecastprotect.com/s/71aaC1wpMjIMXpmj5HLfkfVEGiI?domain=onlinelibrary.wiley.com

The above photo is at Nachusa Grasslands in our East Heinkel Unit, due north of Schafer Knob. On the left is a prairie planting that is about a decade old and frequently burned. It established well and is handsome this time of year with pale purple coneflowers and white baptisia. My photo does not do it justice. It has essentially no shrubs and has been burned every year or every other year since its planting in 2013.

On the right of the photo is a fallow prairie pasture that the former owner sprayed with broadleaf herbicide a number of times and then grazed horses on it. The prairie was nearly vanquished, but some diversity remains. This herbicide sprayed field likely supported shrub establishment. Notice all the shrubs in it. Abundant are smooth sumac, various Rumex briars, some multiflora rose, honeysuckle, cherry, and black oak.

This unit with shrub buildup has not been burning enough to top kill all the shrubs. It is on a gentle north slope which may lower fire intensity. We had shrub buildup in there before bison, and we have the shrub thickets now, ten years after bison have had access to it. The grazing at times makes the fires patchy with low intensity, which has benefits, but likely supports the shrubs.

This winter we hope to brush mow the unit to see if that later helps the fire come across the unit and top kill the shrubs. We work to keep shrubs and trees out of our open prairies to leave some habitat as full open prairie.

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