At Matthaei-Nichols, Collecting Seed Spreads Diversity

Ever wandered through the Arb and Gardens and wondered what happens to all that seed after the flowers fade?

Many of the native plants that grow at Matthaei Botanical Gardens and Nichols Arboretum produce abundant quantities of seed. Collecting and processing the seed ensures robust future generations of native plants. As botanical gardens shift from displays of strictly pretty (and often nonnative) plants and flowers to hardier native types that thrive in their own regions, the practice of encouraging native species continues to grow.

Boneset seeds (Eupatorium) as seen through a seed-sorting screen

Breaking open a rip milkweed pod

A hairdo fluff of blossoming milkweed seeds

Collecting seed from these native plants fosters eco-diversity, explains Connie Crancer, Matthaei-Nichols horticulturist and native plant specialist. “We use the seed, which is collected by volunteers, work-studies, interns, and staff, for restoration efforts in our various ecosystems in our natural areas and for some of our display gardens, and to replenish depleted native seed bank where the soil has been disturbed.” If you visit Matthaei Botanical Gardens in the winter or spring of 2013 you’ll see a good example of a disturbed area along the service drive at Matthaei that was excavated for the new water main. This area was reseeded with a prairie savanna seed mix created in-house instead of being sown with non-native grass seed.

A perfectly formed plug of milkweed seeds seems lit from within

Following collection the seed is allowed to rest—a process called after-ripening—and then dry. Then the seed is removed from the inflorescence or fruit and the largest plant parts are discarded. What remains is the seed along with some of the chaff or floral parts. This process is usually straightforward, such as passing it through a screen, scrunching it with a rolling pin, or using a specially retrofitted house blender. It can be dramatic, too, particularly when fire is used to quickly burn off the plant down from milkweed seeds. The flash burn doesn’t negatively affect germination.

Milkweed down bursts into momentary flame

Getting rid of all the non-seed parts isn’t essential, adds Crancer. Seed companies sell perfectly cleaned seed, free of chaff and other plant material, but Matthaei-Nichols’ goal in seed collection isn't about seed sales, though sometimes the seed is traded with other organizations. "The seed we process is isolated from the floral parts enough for optimal germination and the extra chaff and plant parts that go through the processing is tolerated and actually helps when we direct sow the seed," she says.

Good record-keeping is also essential, with data gathered on when and where the seed was collected. Finally, when all of the seed has been processed, staff and volunteers weigh it for volume and create special seed mixes for restoration and special projects. The remaining seed is packed into plastic bags and stored in a cold room, where it will last for 3 to 6 years.

Photographs courtesy Sarah Michayluk.