Dicentra eximia
There’s a debate raging about whether “Nativars” (cultivars of native species) have the same ecosystem services as the true native species. Take Bleeding Heart as an example – Dicentra eximia is an Appalachian and Green Mountain woodland native with medium-light pink flowers that occasionally produce a white-flowered form. Then there is a cultivar called ‘King of Hearts’ that is always true to color, which is a rich pink. When our native bleeding heart (D. eximia) is crossed with the Pacific bleeding heart (D. formosa) you get the cultivar ‘Luxuriant’ which is cherry red and blooms forever. As a designer I might want a deeper pink in a woodland garden and so I might choose a cultivar, but as an ecological landscape designer I would want to select the plant that provided the most “bang for the buck” in nectar and pollen. Dicentra eximia is a favorite plant of The Roadside Skipper butterfly in May and early June along with hummingbirds and bumblebees – if I select the Nativar ‘King of Hearts’, will it feed just as many Roadside Skippers?
We want to do the right thing and select plant material that can be a food source to wildlife, but we also like flowers that are brightly colored, bloom a long time, and fit into dependable size ranges (compact, tall etc.). So, how far can we stray from the original species? The answer is clear as mud. Thanks to the research of Doug Tallamy we are beginning to understand the issue a bit better, and it has everything to do with leaf chemistry, shape, and toughness. Without further research you can’t assume that a cultivar has the same palatability as the parent species. A grad student at UVM is beginning to conduct research on the pallatability of Nativars, and I look forward to reading her results. Until then, I follow the advice of Vincent Vizachero who wrote a good article about Nativars for the Blog Native Plants and Wildlife gardens:
“my first choice will always be a locally-sourced open-pollinated seed-grown (native species) plant. My second choice will be a cultivar that maintains the flower shape, berry size, and leaf color of the species. My goal is to never buy cultivars that exhibit radically different flower shape or color, but I will knowingly buy dwarf varieties which are otherwise similar to the species.”
I try to stay as close to the species as possible, especially when it comes to Tallamy’s Top 20 – those plants that provide food for the highest number of species. Solidago, Asters, Helianthus, and Eupatorium are the top 4 perennials and also happen to thrive in sunny, moist clay here in VT. Here are some of the cultivars that I use often:
Solidago rugosa 'Fireworks'
Aster novae-angliae
Eupatorium maculatum 'Gateway'
Helianthus divaricatus
The L.A.N.D. Line 