New Native Shade Perennials for 2011
Sweet Wakerobin, Trillium vaseyi: I saw this trillium last spring in a local garden and fell in love with its large red flowers and huge bright green leaves; native species to just south of PA (photo Arrowhead Alpines).
In my previous article, New Shade Perennials for 2011, I highlighted some of the new non-native plants I will be offering at my nursery this year. I also described my blog’s two audiences and my philosophy about what plants I grow in my gardens and sell at my nursery.
This article features some of the 17 native plants that are new (or returning) to my Spring 2011 Catalogue. For a full description of the ornamental and cultural characteristics of these plants, please consult my Spring 2011 Catalogue by clicking here or going to the sidebar of my homepage where it is permanently posted in more manageable chunks. For an illuminating (I think) discussion of why growing native plants is crucial to our survival, please read my article My Thanksgiving Oak Forest in which I profile Doug Tallamy’s book Bringing Nature Home.
I am reluctant to enter the “what is a native plant” fray, but I feel I have to if I am going to use the word native to describe these plants. For the purposes of my catalogue, I treat all plants indigenous to the US and cultivars of and hybrids between those plants as native, always adding a comment on what part of the US the plant inhabits. Most of my natives are endemic to Pennsylvania and its immediate environs. However, many horticulturalists don’t consider cultivars and hybrids of native plants to be native.
To try and address that issue, I went right to the horse’s mouth and asked Doug Tallamy, author of Bringing Nature Home and Chairman of the Entomology and Wildlife Ecology Department at the University of Delaware, where he stood on native cultivars and hybrids.
In responding, Tallamy first pointed out that: “We know very little from experimental data [because] comparisons just haven’t been done yet” between the ecological value of native plants and the value of their cultivars and hybrids. “Insects have adapted to the chemistry of their host plants, so if we don’t change the leaf chemicals too much when making cultivars, most of the insects that use the native parent should be able to continue using the cultivar.”
However, Tallamy cautions: “Most of our cultivars focus on flowers, … and flower energy budgets are very tight. If we make flower petals larger, that may come at the expense of nectar production…or pollen production. Pollinators will visit the new flower but get no reward. Double flowers typically have no nectar production at all…. A big down side of cultivars, even if they do support insects, is that they are clones with no genetic variation.”
Large-flowered Bellwort, Uvularia grandiflora: it is really the full habit of this plant that grabs you in the garden with its many twisting flowers and leaves on upright stems; native species to PA (photo Arrowhead Alpines).
So how do I apply this to my new native plants? Well, of the 12 plants featured in this article, six are straight species native to Pennsylvania and its environs (see commentary under photos). These plants satisfy even the most narrow definition of native. The fern is a native hybrid that occurs naturally in the wild and should be as good as any straight species. The same can be said for the yellow columbine, which is a naturally occurring color variation. The double bloodroot, although double-flowered, was discovered and not created by humans. None of these are clones; they are all seed strains ensuring genetic diversity and vigor.
That leaves only the three heucheras described below. If your goal is to support native insects and through them the whole ecosystem, then purple-leaved heucheras like ‘Midnight Rose’ are not the plant for you. Tallamy says, “if [when creating a cultivar] we change a green leaf to a purple leaf, we are loading the leaf with anthocyanins, which are feeding deterrents for insects.” The same may be true of gold-leafed heucheras like ‘Electra’. Those two cultivars have also been created through extensive hybridizing of several heuchera species native to the US. ‘Green Spice’, however, is a cultivar of a species native to Pennsylvania and probably has leaf chemistry close to its parent and thus beneficial to native insects.
Wild Columbine, Aquilegia canadensis ‘Corbett’: pale yellow and shorter alternative to the bright red species and, like the species, does best in the well-drained but moist soil so difficult to find in my garden; naturally occurring color variation native to PA.
Where do I come out on all this? I really care about this issue so I try to have the majority of my property planted with straight PA native species friendly to native insects. I also think any plant with a native background even if it’s a “created” cultivar or hybrid is better than a non-native for supporting our environment. But I specialize in non-native hellebores and snowdrops, and I have hundreds of them in my garden. Balance in all things, including the garden.
Here are the rest of the new native plants I am excited about:
Dixie Wood Fern, Dryopteris x australis: a naturally occurring hybrid native to just south of PA, the fern growing behind and through my bench in the deep, dry shade of a Japanese maple overhung by a white pine is Dixie Wood Fern on 11/11/10—need I say more?
Indian Pink, Spigelia marilandica: there is no better way to get me going than to write yet one more shade gardening article that starts “Now you may not be able to have showy flowers in the shade, but….” ; native species to PA (photo Arrowhead Alpines)
Double Bloodroot, Sanguinaria canadensis ‘Multiplex’: naturally occurring double flower native to PA, this is my all time favorite flower—I could stare at its perfection for hours—so it has taken me years to get to the point where I felt I had excess to sell!
Bloodroot, Sanguinaria canadensis: so much to love, the way it spears through my leaf mulch, the unusual blue-green leaves, the pure white flowers, and, believe it or not, the short time they last in the garden—it forces me to savor them; species native to PA.
Who can resist the kaleidoscope of colors that heuchera leaves add to the garden and containers? If only all these beautiful plants thrived equally well in our tough mid-Atlantic conditions, but they don’t. I only sell the cultivars whose parents are the heat and cold tolerant heucheras native to the eastern US. Here are three new tough heucheras for 2011:
Coral Bells, Heuchera x ‘Electra’: cultivar parented by two tough species native to PA and one Pacific Northwest species; with leaves and veins like this, who can resist? (photo Terra Nova Nurseries).
Coral Bells, Heuchera americana ‘Green Spice’: straight species cultivar created from our PA native so imminently suited to mid-Atlantic conditions, pumpkin orange fall color (photo Terra Nova Nurseries).
Coral Bells, Heuchera x ‘Midnight Rose’: cultivar parented by two tough species native to PA and one Pacific Northwest species; yes, it really looks like this and is a wonderful plant for containers, but requires a little more coddling in the ground because the Pacific Northwest species is more dominant in this cultivar (photo Terra Nova Nurseries).
In addition to the above and what was covered in New Shade Perennials for 2011, I have new snowdrops, hellebores, and hostas, which will be covered in future articles on those topics.
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The view from my desk this morning: