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.
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Boneset seeds (Eupatorium) as seen through a seed-sorting screen |
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Breaking open a rip milkweed pod |
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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.
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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.
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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.