Growing Native Perennials from Seed

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Unlike many native perennials, Purple Coneflower is quick and easy to grow from seed.

Must be easy to spread yourself around when you’re a plant that produces lots of seeds, right? After all, look at what happens when kids blow the seeds off dandelions! Dandelions pop up everywhere next year!

Unfortunately, it’s an ironic fact of gardening life that whatever you are trying to grow takes some effort, whereas the plants that you don’t want (aka “weeds”) just seem to appear without any help from you.

Now, even though regionally native plants (if sited correctly) tend to be easier than exotic plants to grow in temperate climates such as New England, that doesn’t mean that they will necessarily establish and spread without some help from us. You can buy established container plants from native plant nurseries, but this gets expensive, plus many commercially available natives are cultivars – genetically identical clones that contribute little genetic diversity and resilience to the species as a whole.

Here’s where we hands-on, DIY gardeners come in, by helping nature along a little bit!

The beautiful Butterfly Weed (Asclepias tuberosa) is very rare in the wild, but is easy to grow from seed from existing plants.

The beautiful Butterfly Weed (Asclepias tuberosa) is very rare in the wild, but is easy to grow from seed from existing plants.

In an ideal world, our plants would bloom at the right time, be pollinated by the right kind of insect or bird, form seeds and fruits that ripen and are carried (again, by bird, insect or wind) to an appropriate location to germinate when the weather is just right. Some of them do, and if they survive the first year or two, may become established plants that flower, go to seed and continue the cycle.

In the real world, though, seedlings don’t have a high survival rate. Seeds that are not picked right off the stem by hungry birds might, if they have the misfortune to blow into a lawn or roadside ditch, be mown down repeatedly or doused with weedkillers. Some seedlings are crowded right out by vigorous exotic (non-native) plants that make up about 40% of the natural vegetation in New England. Other seeds will just never germinate, no matter what. Such are the laws of life, genetics, and human-controlled landscapes.

Native plants such as Black Cohosh (Actaea racemosa) are often expensive to buy because they are slow to propagate from seed. Photo used by permission of Vincent Normand.

Native plants such as Black Cohosh (Actaea racemosa) are often expensive to buy because they are slow to propagate from seed. Photo used by permission of Vincent Normand.

So what’s a native plant gardener to do, if they want large quantities of native plants? Why, collect seeds and grow your own, of course! You can help support local plant and wildlife communities and have a beautiful, natural native plant garden by collecting seeds from existing natives and growing and distributing the seedlings around the landscape via friends, family and fellow citizens.

Collect seeds from plants that are as locally native as you can find — in Massachusetts this usually means buying mature flowering plants from nurseries at New England Wild Flower Society’s Garden in the Woods (Framingham and Whately) or our small nursery at Turkey Hill Brook Farm (Spencer). Try to find local plant suppliers that propagate from local seed banks. Avoid buying seeds from foreign suppliers or even other areas of the country–-seeds may not be adapted to grow in your particular climate. You can also collect seeds from native plants that you’ve seen growing and blooming locally – but never take more than about 10% of a plant’s seeds for your own use.

If you don’t have a cold frame, sow native seeds in recycled clear plastic containers with lids and place outdoors for the winter to protect them from critters or floods.

If you don’t have a cold frame, sow native seeds in recycled clear plastic containers with lids and place outdoors for the winter to protect them from critters or floods.

Best Way to Sow Natives?

The easiest way to grow from seed is by simply allowing plants to go to seed and letting nature do the seeding, but you may have little success with this if your gardens are heavily mulched or lots of critters are present to dine on the seeds. Because most native plant seeds need an extended period of time (sometimes several years) before they will germinate,  you’re usually better off sprouting native seeds in a protected area outdoors, such as a cold frame or greenhouse, and letting them take the time they need.

Learn Your Seed’s Needs

Do some homework to find out whether your seeds have any special requirements for germination. For example, our native milkweed and bee balm seeds require at least one winter outdoors in a moist environment before they will sprout. Wild cranesbill seeds are hydrophilic and should not be allowed to dry out in storage. Seeds from wild senna and goat’s rue require scarification/scraping of the seeds to loosen their hard seed coats to allow for germination. I use William Cullina’s book Growing and Propagating Wildflowers of the United States and Canada from New England Wild Flower Society, which lists germination requirements for each plant native to North America. Miriam Goldberger’s new book Taming Wildflowers also lists germination requirements for plants along with other tips for growing wild plants from seed. Prairie Moon Nursery has online germination requirements for the various native seeds that they sell.

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At Garden in the Woods, Trilliums and Squirrel Corn (Dicentra canadensis) are sown in raised nursery beds where seeds can sit through several winters and grow until plants reach their flowering stage. At that time, the best selections are transplanted to the garden or potted up for sale in the nursery.

Rudbeckia and Blue Lobelia (Lobelia siphilitica) are easy to grow from seed sown when they ripen on the plant.

Rudbeckia and Blue Lobelia (Lobelia siphilitica) are easy to grow from seed sown when they ripen on the plant.

Easy Native Perennials from Seed

For your first attempt, try growing the following eastern natives from seed — fresh or dried seeds usually germinate easily without any special treatment (cold exposure or scarification) in New England:

  • Aster
  • Lobelia
  • Helianthus
  • Rudbeckia

Native Seeds that Require At Least 1 Full Winter Before Germination:

Most of our northeast natives will only germinate after being exposed to several months of cold, snowy weather….in other words WINTER. As moisture-filled seeds freeze and thaw through winter and into spring, their outer seed coats break up, signaling seeds to germinate when temperatures get warm again. Locally-evolved plants are smart — their seeds know better than to germinate too early and have their babies get zapped by the cold.

  • Liatris seeds readily germinate in spring after a winter outdoors in moist soil.

    Liatris seeds readily germinate in spring after a winter outdoors in moist soil.

    Asclepias (also needs light to germinate, sow seeds on soil surface)Aquilegia

  • Echinacea
  • Eupatorium
  • Eutrochium
  • Geranium (hydrophilic seeds, do not let dry out)
  • Goldenrod
  • Liatris
  • Monarda
  • Phlox
  • Pycnanthemum
  • Tiarella
  • Verbena
  • Vernonia
  • Viola
  • Zizia

Some native plants only germinate after multiple winter/spring cycles of freezing/thawing:

  • Trillium
  • Actaea
  • Senna*
  • Polygonatum* (hydrophilic seeds, do not let dry out)

If you start early by sowing seeds in fall or early winter after collection, you might be able to coax seedlings from these the first spring after sowing.

img_1422-300x265Winter Sowing in Containers

On our farm, my free-range chickens love to pick at seeds and scratch up seedlings in my plant beds, so I collect seeds from my best plants in fall and germinate them in recycled plastic containers with lids, to protect them until they can germinate and grow a little bit.

Here is the native plant nursery that lives on our patio from early winter and spring each year — by late spring, I transplant seedlings into individual containers or directly into the garden:

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To sow seeds in plastic produce containers, poke holes in the bottom and top of the container, sow seeds on a few inches of moistened seedling mix, water well, and place the containers outdoors for the winter. When warm temperatures arrive in spring and seeds begin to germinate, open the lids on warm days. When seedling roots reach the bottom of the containers, you can transplant them, either right into the ground, or into containers to grow on until they are larger.

Winter sown seedlings grown in containers will be tiny in their first spring, but very hardy! Unlike seedlings grown indoors, they need no hardening off after lids have stayed open for several days and nights.

More Info on Native Plants and Winter Sowing:

WinterSown.org

Winter Sowing FAQs at GardenWeb 

How to Germinate Native Seeds from Prairie Moon Nursery

This article is reprinted from its original posting in May 2014 at the now-defunct Native Plants and Wildlife Gardens.