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North Branch Restoration Project Seed History and Practices

Basic Information


The North Branch Restoration Project, a collection of sites along the North Branch of the Chicago River on Cook County Forest Preserve land and several park district sites, has been involved in restoring natural areas for 41 years. Stewards on the North Branch often think of the North Branch as a single site, so in that spirit I am sharing my thoughts and understanding.

At the first workdays on the North Branch in the summer of 1977, volunteers collected prairie phlox seed and later planted it. In those early days, we were able to collect seed from nearby unmanaged remnants, thus enhancing the original native plant diversity of North Branch sites. Now, sites longest under management are an incredibly rich source of seed. Seeds have been critical to North Branch from the start.


Collecting and Seed Mixes


Currently seed collecting takes various forms.

A regular group goes out seed collecting every Wednesday from late May to mid-November. This group has been in existence since 1985, and has grown steadily over the years, so that currently 9 to 14 regular volunteers put in about 1000 hours each year seed collecting. This group collects from all the established North Branch sites.

Many site stewards also collect seed on their weekend workdays in the fall. Some established sites have additional seed collecting workdays during the week throughout the growing season, and some of the Wednesday group collect on other days as well.
Since 1985 we have had a home garden program where people take rare plants, plant them out in their yards, and collect the seeds. This home garden project focuses on seeds that are very rare or hard to collect. Having the plants in a home garden makes it possible to collect seed from a denser population than is usually found in the wild. The Chicago Botanic Garden originally grew plants for us; now a volunteer with super plant propagation knowledge does this.

The number and amount of seeds collected have increased in recent years, as our volunteer hours have increased and our sites have expanded in size, and become richer in species. (This is one of the big advantages of having a large seed collection effort: it allows you to clear more acreage and have more seed to cover those areas.) We process seed twice a year, in midsummer (spring and early summer seeds) and in late fall. In general, we don’t use mixes for our spring and early summer seeds; we distribute the seeds to stewards on an individual basis. However, one of our sites does put their spring seed into mixes. In 2017, the stewards got about 102 spring and early summer species. Our fall seeds are placed into 12 seed mixes, including about 270 species in 2018. By contrast, in 2011, there were about 170 species in our fall mixes.

We use seed mixes in the fall to simplify seed sowing for stewards. Planting 50-100 species of seeds individually would be an overwhelming task. Our spring seed volume has grown to the extent that we wonder if we should create spring seed mixes as well. Here are our 12 current fall seed mixes: --turf (highest quality prairie) --mesic prairie


  • wet mesic prairie

  • wet savanna/wet prairie --open woods

  • wet mesic woods

  • pond

  • mesic open savanna --wet mesic open savanna --woods

  • wet woods

  • flatwoods


One question that we have considered is adding inoculum to our mixes. In the early days, we did add nitrogen fixing bacteria, to help the legumes get a good start. Some of us have noticed that the

legume seeds in our mixes do not always produce as well, and we wonder if the lack of the right soil bacteria might be a factor.

Seed processing takes place twice a year. Around July, we process spring and early summer seeds in an evening event where around 25 people attend and work for about 2 1⁄2 hours. In late November, we have our big weekend seed processing event, where around 60-90 people work for 5 – 6 hours, with additional time for data recording.


One of the challenges with seed collecting is bridging that gap between the plant in flower and the plant in seed. The Field Museum has a good guide to 72 common prairie plants in seed in our region (but it does not cover all the seed we collect). 919_usa_prairie_seed_heads-version_2.pdf


Our own North Branch Seed Collecting Guide can be found here:

DuPage County Forest Preserve District shared a useful spreadsheet with information about 528 species from DuPage County, including when to collect that seed.


Seed Planting


Spring seeds are planted right after processing and distribution to stewards. Fall seeds are planted in the fall, winter, and even early spring. Seed planting is not an easy task; it takes good judgement to select the right place to plant, and work to prepare the area for seeding.


There are different opinions about the timing for sowing fall seeds. Many stewards wait until after the fall burn season, so that leaves and thatch are burned and the seed makes better contact with the soil. In the woods, some stewards rake leaves or look for leaf-free areas to plant for the same reason. Some don’t plant seeds on snow, worrying the seed is more likely to be eaten by hungry critters. Some wait to sow until the second year after clearing so buckthorn seedlings and re-sprouts can be controlled. Others plant in areas where they intend to clear in the near future. Most people plant in strips or other patterns, expecting that the whole area will fill in with seed from the new plants.


recently had very well received classroom and field training sessions from Steve Packard where we exchanged ideas on where and how to plant our seed mixes based on light levels, moisture, and existing vegetation. Steve also has a blog post on the same subject. Here is the link.


Our sites are constantly changing mosaics of light and shade, wet and dry; we try to match our seeding to those on-the-ground conditions. One change that we are seeing on many wooded sites is the opening up of the canopy due to the death of ashes from emerald ash borers. This creates an opportunity for savanna and even prairie seeding in those places.


Seeds Component of Stewardship Work


For myself, being a seed collector has really expanded my plant knowledge and my understanding of my site. It makes me really look at the leaf arrangements and the plant structure, because the flower with its colored petals is not there to help me. It also makes me aware of plant communities and likely associates.



Many people really enjoy seed collecting. It can be a very thoughtful, meditative experience. There are all kinds of sensual pleasures involved as well. Some seeds have interesting smells, like the spicy citrusy smell of yellow coneflower. Others have great textures, like the kitten fur feel of Indian grass. Some have interesting mechanisms that release the seed, like the explosive seed capsules of witch hazel. Some seeds are edible, like American plum, so you can do seed preparation during a meal. Because seed collecting is a quiet activity, you notice the birds and insects around you. Because it is less strenuous than brush cutting, you can continue it later in life. It appeals to young people as well, because it makes concrete certain natural connections that they may have only read about in books.

But seed collecting is not for everyone. You spend a lot of time just looking, especially at the start of the season. It takes a certain kind of vision, and ability to see patterns. There is frustration when your timing is off and you are too early, or too late. If you want to be effective, you have to go out every week, and this means when it is hot, cold, buggy, going to rain, etc. Nonetheless many people love seed collecting and are happy to participate in it under all kinds of conditions. With a group of regulars, camaraderie builds up, and people take joy in working with each other and celebrating their increased understanding of seeds and our natural areas overall, and the vibrancy and biodiversity of our sites as a result of our seeds.


Expanding the Seed Program


All North Branch stewards could use more seed. Many of our sites have recently cleared areas, as well as areas where native vegetation is thin. Those are the places where more seed can go. Many factors limit seed collecting: availability of volunteers, seed expertise in leaders and volunteers, the weather, and shortage of key seeds. I think people are motivated to collect seed by hearing stories of the success of seed collection, by learning how rare our native plants really are, and by the experience itself. Our leadership encourages seed collecting especially in the fall, recognizing that seeds don’t hang on, while buckthorn can be cut all winter.


Seed Guidelines


Key principles in North Branch seed policy are these ideas: 1) the existing seed bank of a site is almost never adequate to allow the full range of native vegetation to return once woody or herbaceous invasive species are removed; 2) even our remnant areas have lost native species over the years, and so need supplemental seeding; 3) local seeds have unique genotypes that should be preserved. As a result of these principles, the North Branch shares seed across our multiple North Branch sites based on ecosystem types, and only accepts seed from a limited mileage range (15-25 miles). We have a few areas where contractor seed of unknown provenance has been sown by others, and we don’t collect seed from those areas for our seed mixes. Because we had well designed seed policy in place when the District issued its seed guidelines from the Prairie Research Institute, the District re-authorized us to continue our current practices. For sure we can share our seed policy with this group.


I think one of the great future challenges in seeds is going to be the impact of climate change. Will local genetics be able to adjust and handle the rapidly changing climate? Does our focus on local genetics need adjustment? Should we be looking to the south and to the west for seeds? These and similar questions are ones the seed collectors of the future will answer.


Forest Preserve District of Cook County 


North Branch Restoration Project



Why collect seed


Most of our natural areas have become degraded by past grazing, fire suppression, fragmentation, alterations in hydrology, and unnatural competition from aggressive species.  The populations of many plant species have been drastically reduced in size or lost altogether in many preserve areas.  The goal of management is to restore the natural community to a healthy state, one where (assuming the restoration of natural processes, such as periodic fire and movement of seed and pollen) the community becomes self-renewing and self-sustaining, allowing for natural successional processes and evolution to occur. A critical piece of achieving that goal is to restore the natural diversity by restoring the diversity of gene pools and re-introducing those species that research indicates would likely have been present.  In the absence of complete historical records, which rarely exist, we use the best information available to help restore the appropriate community floral composition.  Good guidance comes from studies of nearby similar communities, authoritative references such as Plants of the Chicago Region by Swink & Wilhelm (1994), herbarium specimens, Public Land Survey notes, historic records such as H.S Pepoon’s Flora of the Chicago Region (1927) and similar resources. 


We seek especially to restore the more conservative species, those that are most sensitive to recent unnatural disturbance and the first to drop out in response. We are not unduly concerned about the potential of a species, especially a conservative one, to become a problem in the restoration of damaged communities, such as those on the North Branch. We have seen no indication that conservative plant species have become conservation problems. By restoring diversity, we hope to foster more healthy and sustainable communities and provide more niches to support the faunal component and perhaps attract species that have been lost to the community as a consequence of habitat degradation.


How the plan was assembled and updated


From the earliest days, the North Branch seed plan was carefully designed in a collaborative way, with the expertise coming from the best sources available, including the staff of the Forest Preserve District (FPD). We were very fortunate in that some of the foremost academic and practitioner experts in the region were willing to advise as this plan was assembled. Our initial seed plan was developed with input and review by Roland Eisenbeis (FPD Superintendent of Conservation), Dr. Robert Betz (Northeastern Illinois University), Raymond Schulenberg (Morton Arboretum), Chuck Westcott (FPD Crabtree Nature Center), and Dr. William Beecher (Chicago Academy of Sciences). The early literature consulted included the Prairie Restoration Handbook by Philip Rock and the ongoing studies from which the discipline of restoration was evolving.  North Branch policies were summarized in annual reports to the District. 


Over the years, as additional questions arose and as more people took an interest in the work, our seed plan was regularly reviewed and modified by the NBRP Ecological Management Workgroup with input from additional contributors including Dr. Daniel Wivagg (Loyola), Jerry Paulson (Illinois Nature Preserves Commission), Dr. James Reinartz (University of Wisconsin), Dr. Gerould Wilhelm (Morton Arboretum), Paul Strand (FPD Sand Ridge Nature Center), John Schwegman (Illinois Department of Natural Resources), Ralph Thornton (FPD Land Manager), Richard Clinebell (St. Louis University), Chet Ryndak (FPD Superintendent of Conservation), Ed Collins (McHenry County Conservation District), Tom Vanderpoel (Citizens for Conservation), Doug Ladd (The Nature Conservancy), Dr. Dennis Nyberg (University of Illinois), and others.  This seed plan was also modified based on input from burgeoning environmental restoration literature:  Restoration and Management Notes (later the journal Ecological Restoration), the Natural Areas Journal, Conservation Biology, Restoration Ecology and the Tallgrass Restoration Handbook (Edited by Packard and Mutel).


Not all of these experts agreed with each other on all aspects of the program. But all thought the general approach of the North Branch to be a good one: from procedural, scientific and practical perspectives.


In August 1992, the North Branch Restoration Project published a “seed ethics” document, summarized below; the editor of that document was Karen Holland (Rodriguez), and it was published in the North Branch journal of that time, Prairie Projections.





Because most individual North Branch restoration areas were so small and of only fair or good quality, experts feared unnatural “founder effect” and depauperate gene pool problems if restoration were limited to seeds from within each small area. Thus, the plan that was approved called for gathering seeds from spontaneous populations at a wide variety of nearby remnants. When the plants resulting from these seeds began to interact with each other and with those plants of the same species (if any) that remained in a given area, the expectation was that the most local alleles would likely prosper over time, but perhaps be more or less frequent than historically because of changed conditions (now wetter, more heavily browsed, higher nitrogen levels, global climate change, etc.). It was also thought that the populations would likely benefit from alleles needed for disease resistance, environmental extremes, etc. that had not survived in the small remnant populations.


Especially in the early years when it was possible to do so, seed gathering concentrated as much as possible on remnants that were in danger of destruction. In fact, most of the seeds came from remnants that have since been destroyed. These include the Chevy Chase Prairie on the Lake Cook line in Wheeling (widely regarded as the highest quality prairie in Illinois before it was bulldozed to make a business park), the Des Plaines railroad triangle (now a Wieboldts Warehouse), and a large number of similar areas, including many unmanaged forest preserve areas where the diverse native vegetation is now also gone. Thus today, both the original and the restored species of the North Branch restoration areas have added conservation value because they contain the genetic information from a wide variety of local populations, many of which are now otherwise extinct.


Collection of seeds


Learn about the sites from which seed is to be gathered and which will receive the seed, the plants seed is to be collected from, and the people who will be collecting.

  • Determine the best methods to avoid or reduce the impact of people trampling to collect.

  • Obtain appropriate permits to collect on public lands and permission to collect private property.

  • Train seed collectors in techniques that maximize the survival of the donor plant and the retention of the collected seeds, while minimizing the collection of unripened seeds.

  • Utilize pre-settlement and post-settlement historical records to determine the habitat classification of the site which will receive the seed.

  • Collect from and deposit seed on sites which are geologically similar and/or biologically connected.


Tend the collection by gathering ripened seed from known plants, leaving seed for regeneration and for animals, and ensuring donor plants remain intact.


  • Monitor plant populations for seed ripeness often – in order to collect at the appropriate time.

  • Pick seed only from plants that have been positively identified. (In the case of difficult sedges, label bags of unidentified species with associates or habitat types (e.g. mesic woods or wet prairie). 

  • Collect seed from endangered or threatened species only with proper authorization.

  • Delay harvesting of species in which segregating ripened and unripened seed is difficult or impossible until most seeds have ripened.

  • Harvest no more than 50% of seed on a site from perennials and 25% from annuals and biennials.

  • Remove and transfer plants from a site that is being destroyed to a protected site under the supervision of a qualified plant ecologist.

  • Document what kind of seed is collected, where it is collected from, and how much is collected in order to add to the records of site dynamics.


Share the harvest as soon as possible with those who will sow thoroughly processed seed as mixtures on prepared ground.


  • Process seed in a timely manner using proven techniques. Prepare seed mixtures according to community type.

  • Clear only enough ground at degraded sites to accept the quantity of seed available.

  • Prepare sites with an established plant structure (by burning, scything, etc.) to make them more receptive to rare seed from more conservative species, in order to establish more natural diversity.


Protect the seed that is not sown by storing in a manner that effects continued viability.


  • Find storage space for seed which is not immediately planted.

  • Store seed as required by individual species and seed mixes. (Never store seed in a hot car, even for a short time. Never allow seed to mold or dry excessively.)


Nurture the plantings by managing the site.


  • Always control brush seedlings and re-sprouts before seeding. This work may take a full year in difficult areas.

  • Manage the seeded area using accepted ecological restoration practices.

  • Monitor the site for the emergence of plants expected from the seed mixture and for threats from undesired, invasive species.




For the ecological reasons stated previously, during the 1970s and 80s, the North Branch volunteers, as a matter of policy, collected from many varied areas. These included sites in danger of being destroyed, trail edges, and railroad rights-of-way. 


We looked for spontaneous populations on soils like those in the restoration areas (for example, not sand). Since we knew of populations of most prairie species within 15 miles, we decided to limit our search to that distance from the North Branch preserves. When we began to look for oak savanna and open woodland seeds, we found we needed to go farther afield to find the species that once lived along the North Branch. In the case of these species, we set our collecting limit at 25 miles. If species documented from the North Branch area were unavailable at even that distance, in the case of a small number of species we obtained them from the closest spontaneous source (see “Major Seed Sources – North Branch Restoration Project). 


In more recent years, most threatened sites have been destroyed, and more diverse seed is available from restored North Branch areas, so most seed now comes from restored and spontaneous populations of North Branch sites.


It is the policy of the North Branch to collect and sow as many species of the original native plants of the North Branch region as possible, with the exception of some seemingly aggressive species such as Mertensia virginiana, Rubus spp, Eupatorium rugosum, etc.  Experience has also led us to reduce collected quantities of Andropogon gerardi, Sorghastrum nutans and other somewhat aggressive species.  Nor do we collect large quantities of those species that are doing quite well on their own at most areas, such as Aster sagittifolius drumondii, Aster lateriflorus and others.  Before collecting seed at a managed area, advice is sought from the stewards. 


The North Branch also realized early on that there were some species with too small populations or too difficult to collect in the wild to gather significant quantities of seed.  So a wild seed garden program was begun.  Wild seeds of challenging species were taken to the Chicago Botanic Garden to be germinated.  Some of these plants were restored directly to the wild. Most plants from these seeds were given to volunteer gardeners who committed to care for the plants, enjoy and learn about them, and then collect the seed and return it to be used in NBRP restoration work.  The community of “wild seed gardeners” has grown into a group of over 100 gardeners who in aggregate grow about 100 species, collecting and returning large quantities of seed that simply couldn't have been collected in the wild.




The North Branch prairies, savannas and woodlands comprise one long, linear site, and have been treated as such for three decades by the NBRP under the guidance of the Forest Preserve District of Cook County. The macro-site is fragmented by suburban development into micro-sites such as Bunker Hill, Harms Woods, Watersmeet, etc.


The mixes produced from the annual harvest are distributed to NBRP site stewards based on the amount of work that has been done in the respective communities on those areas, and thus varies from year to year.


From the beginning, the North Branch has had a policy and practice of not introducing seed to high or very high quality sites. It seemed to be a prudent and conservative course to manage such areas only by fire and the removal of invasives. For this reason we do not introduce our seed mixes into the very high quality areas of Somme Prairie, Morton Grove Prairie, Glenbrook North Prairie, Edgebrook Flatwoods, and south Harms Woods. In the case of a few very conservative species that only prosper in mature communities, those species have been seeded into high quality areas as approved.


For a time, we also reserved some experimental areas free from seed introduction to test for seed bank release. In wet-mesic, mesic and dry-mesic areas, we have found the seed bank to contribute little; without seeding such areas tend to return to brush or, in some cases, are colonized by whatever weedy species are nearby. The few species that have apparently emerged from the “seed bank” include Geranium bicknelii, Geranium carolinianum, and Chenopodium hybridum. 


Bare soil areas pose special problems and may be the most critical to seed.  Opening an area that has little to no herbaceous ground cover is an open invitation to erosion and weed incursion.


Somme Prairie Nature Preserve


Even before its dedication as an Illinois Nature Preserve, no seed was introduced to Somme Prairie. Since its dedication, it has been managed according to specialized principles approved by the District and the Illinois Nature Preserves Commission in the site management plan. According to that plan, no seeding is ordinarily done in the very high quality (“Grade A”) portion of the preserve.  (Exceptions were made for seeding of three endangered species, which do best in high quality areas.) 


In recent years, the Illinois Nature Preserves Commission has updated its policy on restoration seeding to encourage restoration of degraded areas in nature preserves with seed from similar nearby areas. Under the new policy, approval was granted to use the appropriate standard North Branch mixes in Somme Prairie Nature Preserve.


Revised: December 2018









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