Sustainable Plants Revealed

My recent column on Sustainable Gardening promised a part 2 in which I'd list all the sustainable plants I could conjure up for this part of the world, and here it is.  The impetus for compiling such a list was reading the National Wildlife Federation's recommendations for sustainable gardening practices, which includes the directive to use native plants, period.  Well.  Readers won't be surprised to know I'm critical of generic gardening advice directed to all 300 million of us (or even worse - all of N. America). And how anyone can expect the almost exclusively woodland plants native to the East Coast to be drought-tolerant, even in full sun, is beyond me.  Can this be ideology trumping reality?  (By the way, notice what Ed Snodgrass has to say about whether native plant are suitable for green roofs - or not.  Check his website's FAQs.)  Me, I can't imagine gardening my whole property using just the plants on this list of natives.

My sources for the list started with every website I could find but included many respected hort experts and native plant advocates in the D.C. area and I thank them all.  Now gardenbloggers and readers, what can you add?

"GARDENING COACH" COLUMN FOR NOVEMBER 2006

Okay, a quick review in case you didn't memorize Part 1. Sustainable gardening practices are those that don't damage the earth or waste resources.  Definitions vary all across the board but that one has broad support.  And for eco-conscious local gardeners I've looked far and wide for plants that are:
    - Drought-tolerant.  Since most drought-tolerant plants are Mediterranean and need good drainage if they're to survive our winter and esp for winter and wet springs. So berms are helpful, plus well-draining soil a must.  Also, no low spots or poorly draining clay soils.  And if your site is a consistently soggy one, drought-tolerant plants won't work.  (Google plants for wet soils.)
    -Resistant to disease and severe insect damage.  Minor insect damage?  Get over it.

GOTTA BE NATIVE?
Another criteria for the "sustainable" label used by some sources is that plants be native, a word I interpret to mean locally native.  (Why?  Because no other definition makes any sense.  Plants don't behave according to political boundaries like "native to the U.S.," and the U.S. includes waaay too many different ecosystems to provide horticultural guidance in the first place.) Here in the Mid-Atlantic area the native ecosystem is that of deciduous forest and almost all the native plants are woodland, shade-loving ones, not the desert or rock garden plants that tolerate sun and drought.  So I've included as many locally native garden plants as I could find but there just aren't many to choose from.  (The Plains of the Midwest do provide a considerably larger selection, however.)   

A FEW DISCLAIMERS
    - Even the most drought-tolerant plants for our area require careful watering during their first year, sometimes longer.  So don't assume a plant is drought-tolerant until at least its second full season.  This is especially true of any plant installed in the spring (which is why fall planting is best!)
    - I found contradictory information about some plants, with the literature saying one thing and local gardeners another, so I've noted them as "possibly" sustainable.
    - Some plants listed here are on watch lists for possible invasive behavior because of reports from other parts of the country (nandina, liriope, ornamental grasses, butterfly bush, and daylilies) but no locally listed invasive plants have been included. 
    - I've used primarily common names for reasons of space and public recognition.       

LOCALLY NATIVE SUSTAINABLE PLANTS
Grasses: Big and Little Bluestems.
Perennials: Threadleaf coreopsis, Liatris, Rudbeckias (including black-eyed susan), goldenrod, common evening primrose, Butterfly milkweed, wild columbine, New England aster, wild bleeding heart and possibly Amsonia, Bee balm and Joe Pye Weed.
Shrubs/small trees: Flame azalea, American beautyberry, Serviceberry, several sumacs, Witch Hazel and Pasture rose

SUSTAINABLE PLANTS THAT AREN'T LOCALLY NATIVE
Grasses: Carex, Dwarf mondo grass, Liriope, and most larger ornamental grasses
Perennials: Agastaches, Asters, Baptisia, Chinese Fringe Flower, Daylilies, Dianthus, Epimedium, Hellebores, Heucheras, Hostas, Mazus, Purple coneflower, Rudbeckias, Sedums, Penstemon digitalis, Russian sage, Salvia (hybrid sages), Sempervivums, Sweet Autumn clematis, and Yucca.
Shrubs/small trees: Abelias, Aucuba, Azaleas, Beautybush, Butterfly bush, Caryopteris, Cotoneasters, Crapemyrtles (especially those with Indian names), Deutzia, Forsythias, Fothergilla, Hydrangea paniculatas, Oakleaf Hydrangea, Asian and hybrid dogwoods, Junipers, Lespedeza, Mahonias, Nandina, Photinia, Rugosa roses, Sarcococca, Spiraeas, Viburnums, Witch Hazel, Weigelia, Winter jasmine, Yaupon holly, and Yucca.

PARTING SHOTS
    - These popular plants in our area really don't like drought: Japanese maples, snowbells, rhododendrums, big-leaf hydrangea, boxwoods, and our native dogwoods (Cornus florida). These dogwoods flunk our sustainability test because they're vulnerable to the disease anthracnose. (SP?)
    - Some drought-tolerant plants (like artemesia) have been excluded here because they hate our humidity, so ask enough questions of the nursery staff.
    -Got some plants that always look sickly or that require constant vigilance during even moderate droughts?  Consider getting rid of it.  You'll be glad you did.

Thanks to my contributors: Larry Hurley of Behnkes; Peggy Bowers, horticulturist at the American Horticultural Society; Jim Adams, horticulturist at the British Embassy; Pat Howell of Deephaven Landscapers; Mike Welsh, Takoma Park's City Gardener; Donna Shipp, horticulturist at American Plant Food; Joel Lerner via the Washington Post; Derek Thomas, local landscaper; the highly respected Carole Bergman and others in the Maryland Native Plant Society; the NC State Cooperative Extension Service website and other many other websites.

Comments

[firefly]

*Thank you* for the practical advice! This list, and the Part 1 column at Takoma Voice, are the most concise references I've found yet for the East Coast.

I have some of the plants on the list already, but I'll be looking for more in the spring, so I've printed copies for reference.

Also, good on you for working with the NWF -- I went through the application but saved it without sending the fee because I thought the requirements were not really serious. Maybe now I'll actually go in for that sign, and display it for the neighbors to see :-)

[Xris (Flatbush Gardener)]

Any plant, native or not, used inappropriately will require more maintenance and resource "inputs" and be less sustainable. Species also show variability along ecological gradients, for example: from marsh edge to dry uplands, or from warmer southern to colder northern ranges. That's one reason I try to find out the origins of plants available through mail-order.

It's not that plants from the East Coast are all woodland plants. There are wet and dry meadows, swamps and bogs, dry dunes and cold rocky alpines. Every region has different environments and conditions from which native plants could be selected, promoted and propagated for garden use.

But plants from these different areas cannot be found by the home gardener. The problem is, and has been, commercial availability. The full range of potential garden plants are not propagated or distributed.

I'm not a native plant purist by any means. I assert there's value in using native plants, when possible, which go beyond their garden utility. Our gardens can serve as arks, helping to preserve genetic diversity. We can learn to recognize these plants in the wild, and appreciate what's around us.

The time is coming when many native plants will be unable to adapt quickly enough to climate changes to survive on their own. Like it or not, we will have to become gardeners of the earth.

[Trey]

"Native plant landscapes will flourish even under stressful drought conditions," said Jean White, landscape designer at the National Wildlife Federation.”They are able to adapt to the irregular rainfall patterns that Mother Nature imposes." When we were in the midst of our latest drought the Ponderosa pines were dying in the forest at an alarming rate. Entire swaths of forest were attacked by beetles because of the drought. So native plants can suffer and die due to drought.

It’s all wording. Couldn’t we also say “Xereriscape landscapes will flourish even under drought conditions?” How about this quote from the NWF, “In addition to their water conservation benefits, locally native plants are more wildlife-friendly, providing the best overall food sources for backyard birds and other animals. Native plants may support 10-50 times as many species of wildlife as non-native plants” Is this true? Why do the deer look longingly at my plants through the fence? I would bet given the choice the deer would eat my “foreign” plants quicker than the native vegetation. That why I had to put the fence up. The nursery is full of birds who find it fun to eat the petals of rudbeckia, and berries of pyracantha.

“Trees, shrubs, ground covers, prairie or meadow patches are much better environmental choices than lawn or other non-native plant species.” Really, native plants are much better environmental choices than non-native species? Isn’t that a bit subjective? Why are they much better?

This native plant worship is a bit odd. It’s driven by an urge to get everybody to “Go native”. Not satisfied with tending their own gardens some people and groups want to tend your garden for you, whether you want them to or not.

[Gloria]

If water conservation were my only concern then I would be limited in the native plants available for use. But my concern is the insects and many small creatures most people know nothing about. Honey bees are pretty much adaptive to any plant combinations to find pollen and nectar. But many native bees are reliant on specific plants with specific shapes and bloom times. Everyone knows Monarch butterflies will gather nectar from diverse sources but the eggs will only be left on Asclepias many of which are native to specific areas.This list is long for anyone wanting to understand. Many of the insect world especially the pollinators are reliant upon gardeners and agriculture gaining a different perspective.The generalist such as deer and rabbits and mice will be abundant the way things are now. Is this all you would like to preserve in nature, those creatures without special needs? What a sad world this will be if that were to happen.

[Matt]

Something I learned just a few years ago, plants with multiple tiny blooms are very important to most small pollinators. Much more valuable insect wise than a 10 inch Discobelle Hibiscus.

Thanks for a great list of plants!

[Jay]

Most viburnums are not insect resistant in the least. While aphides like them, and are easy to get rid of with a blast of water, the Viburnum beetle and larvae will destroy these quite quickly in a matter of days. Unless you want to keep vigil over them all summer, expect to lose viburnums to this insect. (There are resistant species, but nothing is 100% safe).
As for Junipers, they can tolerate drought, but they do like water and well-drained soils. Don't be surprised to see mildew and apple-cedar rust bring down a stressed juniper. If you see junipers with a lot of dead patches, look closely for signs of rust. If you live in an area with apple trees(hawthorn, crabapple, etc...) or cedars, you will meet this wonderful fungus soon enough. There is no known safe/organic control.