By Nancy Cleeland and Kasha Helget. Photos by Toni Genberg unless otherwise noted.
Looking to attract more insects, birds, and other wildlife to your garden by planting native species? Bravo! With only about 10 percent of our region dedicated to conservation lands, private native gardens are essential for maintaining healthy biodiversity.
But not all “native” plant species are created equal. It’s important to know the difference between true local native plants and cultivars—plants that go by variations of the same name but have been selected for size, color, bloom time, or even “pest resistance.”
According to Alonso Abugattas, Arlington-based author of the Capital Naturalist blog, research increasingly shows that the quest for prettier, smaller, longer-blooming or more vigorous varieties of popular natives is making many of them less attractive or useful to insects, birds and other wildlife. For example, bigger flower petals may come at the expense of nourishing nectar. The same chemical change that leads to redder autumn leaves might turn off an insect looking for a bite.
Not all changes introduced by cultivars appear to hurt their relationships with wildlife, but it’s still unclear what factors are at play. Until more is known about these relationships, choosing a straight native will always be the safest choice, said Abugattas.
“Why take a chance on using a cultivar that may or may not support wildlife,” he asked, “rather than just choosing what generations of the birds and insects have already chosen through evolution?”
Instead of a cultivar, try a different local straight-species native plant
Matt Bright, who is Conservation Manager at Earth Sangha, the premier supplier of local native plants in the region, said he’s sympathetic to homeowners and landscape designers who use cultivars because they want a certain look or are bound by homeowner association rules.
At least native cultivars are not harmful in the same way that non-native invasive species are, he said. “But I think sometimes cultivars become a crutch rather than grappling with difficult plant selection questions,” he added. “Maybe instead of dwarf hydrangea, there was the opportunity to use a straight-species Lowbush blueberry [Vaccinium pallidum] or a Mapleleaf viburnum [Viburnum acerifolium]?
Or instead of planting a ‘gro-low’ fragrant sumac, you could try a Shrubby St. John’s Wort [Hypericum prolificum] or New Jersey tea [Ceanothus americanus]?”
Bright, who oversees seed collections and cultivation of local plants that are used in restoration projects throughout the region, said that when it comes to supporting wildlife, the more local the plant source, the more likely it will be to attract local wildlife.
That’s not to say that wildlife lovers should rip healthy cultivars out of the ground and replace them with locally sourced natives. After all, the cultivars could be providing some value.
“Like most things in nature it’s complicated and there are a lot of moving parts that we don’t understand fully,” Bright said. “That said, I think the evidence is clear that genetically diverse, locally-adapted, straight-species native plants are the gold standard for restoration and are an excellent choice for garden use.”
Looking for a place to purchase local straight species plants? This is one of the best times to find them at Spring native plant sales.
Armed with the right information about particular natives and their suitability for your location, you’ll be able to choose plants that will support local native wildlife AND beautify your yard. It’s a win, win!