Seed, Transplant, or Just Let Nature Take Its Course? Some Considerations.
As I walk through my woods in spring and early summer, I usually stick to the trails. I want to avoid stepping on any of the beautiful little plants.
There are red trillium, Canada mayflower, false Solomon’s seal, bluebead-lily, and trout lily. Starflower, bellwort and pyrola. Bluets and northern violets and goldthread. And the queen of them all: the pink lady’s slipper, one of North America’s gorgeous terrestrial orchids.
My family’s woodlot, like so much of the northeastern forest landscape, is former farmland. Over the 25 years that we have owned the land, I’ve noticed the wildflowers are spreading, and the number of species is increasing. The return of these beauties shows, I think, the resiliency of the forest.
The trilliums, which had been confined to a few spots along the shaded stone walls, are migrating throughout the woods. The pyrola that grew in one small spot along a lane five years ago have spread all over. Only a few years ago, we had one pink lady’s slipper along our walking trail. Now we have six.
I attribute the increase of our forest flowers to the buildup of leaf litter. We use the forest lightly, cutting only about five cords of firewood and using ultra-low-impact logging techniques and equipment. I’ve noticed that in areas where I’ve thinned the trees, the wildflowers have spread after a year or two, probably because a little more sunlight is hitting the forest floor.
It got me thinking: Are there ways I could encourage more wildflowers? What about bringing in plants from elsewhere, or buying seeds from one of the many native plant seed companies?
The answers turn out to be complicated.
Spring ephemerals, especially, are difficult to propagate. These are the early flowers that bloom and fade in the few weeks between snowmelt and the trees leafing out, and casting shade. These flowers’ seeds may take years to germinate, and their success is closely connected to the soils and fungi, explained Heather McCargo, the executive director of the Wild Seed Project. Her organization works to educate people about native plants and encourage their use in garden settings. Ephemerals, she said, are great examples, of “wildflowers that don’t want to be tamed.”
The pink lady’s slipper, for instance, requires highly acidic soils. It also depends on soil fungi at every stage of its life cycle. Trillium seeds are also notoriously slow to reproduce, McCargo noted, with germination after the second winter and seven years for the first flower. The seeds of false Solomon’s seal may take two years to germinate, and the plants may need another five years to bloom.
“I have grown all the slow growing woodland wildflowers,” McCargo said. “They just take time. Just like growing trees takes time. If we want these plants in the future, we need to have a little more patience with them.”
Seeds of some native wildflowers can be latent in the soil for decades, biding their time for favorable growing conditions. This may be a reason for their sudden resurgence on my woodlot. “Some seeds remain viable for a century or more,” explained Arthur Haines, research botanist with the Native Plant Trust.
Also consider the habitat requirements of individual species. Many native plant reference books include this information (Donald Leopold’s Native Plants of the Northeast is one example). The Lady Bird Johnson Wildflower Center’s website, is a helpful online resource.
One of the best ways to understand a site’s potential to grow wildflowers is to go out in the warmer months and observe. How much sun hits the forest floor? Is the soil constantly wet, or does it drain quickly? How deep is the leaf litter? What other plants are already growing there, and what do reference sources say about these species’ requirements? If you have a forest management plan, check if it has information about soils. If not, the Natural Resources Conservation Service has helpful soil maps on its website.
It’s also important to be realistic. If your woods is a north-facing hemlock stand, its wildflower potential is pretty much nil. “It’s just how that community is – deeply shaded with few understory plants that can tolerate shade,” said Haines.
In dense forests, particularly young ones, thinning the trees will open up the forest floor to sunlight, especially in the spring. But, be careful. It’s easy to overdo it. “If you thin too much, you’re going to get raspberries or poison ivy or invite in invasive species,” said McCargo.
Perhaps no aspect of the “adding wildflowers to your woods” question is as controversial as transplanting.
There is, of course, the issue of what to transplant – not only what is going to grow, but also where you obtained it, and is it appropriate for the site. The worst-case scenario is that you transplant an invasive exotic and watch it take over your woodland. I love the yellow flowers that sprout on my land across the road in the very early spring. But I wouldn’t think of moving them. They are coltsfoot, considered highly invasive in much of our region. So, no to that.
Sometimes it’s not easy to determine what qualifies as native. Lily of the valley, for instance, is often billed as one. But of the three varieties growing in eastern North America, only one is native. And even that is not original to every landscape or location. The USDA Plants Database has maps showing where a plant is native, where it has been introduced, and what its status is.
Which leads to genetics. If you’re buying plants or seeds, it’s important to know where they originate.
“For any plantings in a natural setting, be it for restoration or aesthetics, we strongly encourage using only common species, and ideally of local provenance,” said Bob Popp, state botanist at the Vermont Department of Fish and Wildlife. He explained that, although many of the region’s rare, threatened or endangered plant species are available commercially, his department discourages planting them outside of horticultural settings. This is to avoid or at least greatly diminish their chance of interbreeding with native populations.
Many horticultural specimens derive from mid-western stock, Popp explained, and they aren’t well adapted to northeastern growing conditions. Putting them out in the woods can result in interbreeding with pure native plants, and a loss of local genetic traits. “It also confuses our assessment of what is truly rare in the state, if horticulturally raised individuals escape into the wild,” he said.
As for transplanting local wildflowers, there are some caveats. Don’t move rare plants, don’t collect without permission, and take only from healthy populations. According to the US Forest Service, poaching in national forests is a big problem, threatening rare plant populations.
McCargo is not a fan of most transplanting, even when the flowers are coming from the same property. “Anyone who has these plants in their woods is lucky,” she said. “They shouldn’t go into their woods and move them. They’ll just kill them.” Instead, she recommends collecting and planting seeds as a better way to establish new populations in the woods.
Even planting seeds is complicated. Many forest wildflower seeds require a period of cold before germinating, called stratification. Some require two cold periods. Some have hard seed coats that must be roughed up, or scarified, before germination; some need the fleshy pulp around the seed removed. Some require light to germinate, others don’t. The Lady Bird Johnson Wildflower Center website has a primer on collecting, handling, and storing wildflower seeds. There’s excellent practical information on the Wild Seed Project’s website, on how to raise native wildflowers from seeds.
In the end, I may try to establish a new population of blue-bead-lilies by moving a handful of the plants. Or, I may collect some seeds and plant them. And I may try a few packets of native woodland wildflower seeds, for species that grow in the area but are absent from my woods. If any of this works, I’ve given myself a beautiful gift. If it doesn’t – nature is fickle.
The one thing I will surely do, is continue to observe: what wildflowers are there, which ones are spreading, which new ones are moving in. And I’ll continue counting my lady’s slippers, until there are too many to count. I should be so lucky.