Harvesting Native Seeds

Leah Harrison, Natural Resources Volunteer Coordinator

As everything else winds down for Fall, many plants are hard at work producing seeds to grow the next generation. During this time, the Metroparks Natural Resources Department, along with the help of volunteers, begin to harvest seed from native plants for use in degraded areas. To restore these degraded areas and expand healthy ecosystems in the Metroparks, native Michigan species and their seeds are essential. In the absence of natives, invasive plants create habitat that wildlife has trouble adapting to. Native insects and other animals co-evolved with native plants and are adapted to the specific habitats and nutrition native food sources provide. Invasive plants produce fruits not unlike fast food: they taste good, but they’re not the healthiest! Healthy ecosystems also help preserve biodiversity and our ecological heritage. Many of these plants have historical uses or stories and are one part of the huge tapestry that is the American landscape.

Seed harvesting is cost effective, helps build new native populations, and preserves Michigan genotypes. These native genotypes are important because purchased seed can be expensive or from aggressive strains that may dominate a native Michigan ecosystem. Local seed harvest ensures the origin of the seed and gives the harvester more control over picking an appropriate genotype. Native seed is harvested from restored areas of the parks with large, healthy plant populations. In the fall, this often happens at the prairies of Kensington, Stony Creek, Indian Springs, Lake Erie, and Oakwoods. Prairie species are targeted due to their high populations in the Metroparks and ease of collection. Most prairie plants begin to go to seed in mid-September and continue through October. Throughout the rest of the year, small amounts of species are collected by employees in high quality woodlands. All seed is hand collected and no more than 50 percent of the population is ever taken in a year. This allows enough seed left for wildlife consumption and reseeding of the population. The method of harvesting depends on the species. Grasses can be easily stripped off by hand, but some wildflowers require the whole seed head to be collected.

The collected seed is taken back to Metropark facilities and laid out for two weeks on tarps to dry and to allow any insect hitchhikers to escape. Afterwards, the seeds are cleaned if necessary. If whole seed heads have been collected, they are blitzed in a food processor to release the seeds from the heads and then seeds are sifted out. All seeds are stored by species and location in brown paper bags and plastic containers to prevent being a snack for mice. Any remaining plant material is collected and returned to suitable ecosystems as it may still contain some seed.  The seeds overwinter in storage until late winter or early spring.

In the winter and spring, the stored seed is returned to areas that have zero or few native plants. This is done by hand to best mimic natural processes. Winter spread seed has the chance to be slowly worked into the soil during the freeze/thaw cycle. In the spring, the seed is spread in areas after a prescribed burn is performed- giving it plenty of nutrients and light to grow. The plants require a few years to establish and mature, but the results are an enriched community that is better equipped to support native pollinators and other animals!

Seed Harvesting is a fun, inexpensive, and effective way to grow the populations of native plants within the Metroparks. If you would like to join in the fun, look for volunteer opportunities starting in September of 2020!