Defining “Native Plant”
With a short glossary of ecological landscaping terms: exotic, naturalized, invasive, etc.
Rocky Mountain bee plant
Dear Avant Gardener, I have a small garden where the lawn turns green after the snow melts and then turns a beautiful brown for the rest of the hot, dry summer. The only thing I have planted so far is Russian sage and some native grass. I would love to add wildflowers that I do not water. My daughter, who turns six late January, might enjoy bird or pollinator habitat. What do you recommend? — Bill, Eagle, CO
You beg the question: What is “native,” anyway? I often extol native plants’ ability to thrive without watering — and that’s absolutely true about plants native to an ecosystem. However, databases categorize nativity by state or county. And county-level nativity is not helpful for picking “right plant, right place” when rainfall in the county varies by as much as it does.
“Native, non-invasive” is redundant.
Questions from readers reveal understandable confusion about ecological gardening terms — I mean, this is new for almost everyone — so I’ve listed brief definitions in “Why” below. Importantly, “native” must refer to a place. Most seed and plant retailers call “native” anything native to North America — technically correct, but useless as far as finding plants that will survive without irrigation, support endemic wildlife, and celebrate its uniquely beautiful landscape.
It is difficult to determine what’s truly native to in some places — for example Eagle, Colorado, where a reader is interested in birding with her young daughter. The town is in the Southern Rockies Foothill Shrublands Level IV EPA ecoregion, whereas Vail is in the Southern Rockies Sedimentary Subalpine Forests; however, there’s little info on the ecoregion’s wildflowers. Colorado is not like the northeast, where the climate is fairly consistent and plants spread across many states as they moved north after the last ice age. Nor is it like California, where the state native plant society maintains highly accurate plant range maps.
To find wildflowers that will nurture birds and pollinators without watering, I started with a list of plant genuses that host the most moth and butterfly species in Eagle County. Solidago (goldenrod), No. 1, hosts 79 species, for example. Then I looked into species within them native to the county, focusing on those less familiar to me in an effort to identify ones unique to the Rockies. (“Rocky Mountain” in the common names helped.) I confirmed their ability to thrive with only 11 inches of rain per year, then checked availability — which turned out to be the greatest constraint.
Birds need caterpillars. Full stop.
Focusing on moth and butterfly hosts is important for two reasons: First, many moths and butterflies can only use specific species as hosts (think monarchs and milkweeds). Second, 96 percent of terrestrial bird species rely on the caterpillars of moths and butterflies — not seeds and berries — to feed their young.
Here are the resulting three species I recommend Eagle, Colorado. I suggest you plant masses of each — as many as fit that you can afford — in bands from tall to short. Reserve for spring now; nurseries can have trouble sourcing to meet demand. You should be able to plant them right into your lawn, from back to front:
Rocky Mountain penstemon (Penstemon strictus) spring blooming
Rocky Mountain bee plant (Cleome serrulata, syn. Peritoma serrulata) summer blooming, seeds
Rocky Mountain goldenrod (Solidago multiradiata) late-summer blooming
Even native plants benefit from supplemental water to establish. Can you plant them and then hand water deeply (one inch) each week with no rain? Watering the first three weeks after planting is most important, but a full first season would be best. After that, your wish to have wildflowers without watering will come true.
To build excitement about this project, you might consider giving your daughter coloring books of birds and butterflies, and small, durable 8 x 25 binoculars for her upcoming birthday. (And consider getting yourself the same binoculars in another color, as well as a Colorado bird guide.) #paidlinks
Happy birding!
— The Avant Gardener
Why, How, Wow!
Why?
Plant origin terms are often misused. Here’s a short glossary to help you both select plants and participate in conversations about this increasingly hot topic.
Cultivar: Produced by selective breeding; often either clone or hybrid, so offspring from seeds may be different from parents (e.g., Cercis canadensis 'Forest Pansy')
Local ecotype: Subspecies adapted an area’s particular environmental conditions
Exotic: Non-native
Introduced: Living outside its natural range as a result of human activity; non-native
Invasive: Defined by executive order as a species that is
Non-native (or alien) to the ecosystem under consideration; and
Whose introduction causes or is likely to cause economic or environmental harm or harm to human health. – USDA
Nativar: A variant of a native plant, either bred or found in nature (see variety) and brought into cultivation
Native: Species occurring naturally in a particular region, ecosystem, or habitat
The word native should always be used with a geographic qualifier (that is, native to New England [for example]). Only plants found in this country before European settlement are considered to be native to the United States. — USDA
Naturalized: Established and living wild in a region where it is not indigenous
Straight species: Not a cultivar; indicated by two-word latin name in italics, with genus first and capitalized (e.g., Cercis canadensis)
Variety: Species variation found in nature and usually true to type (e.g., Cercis canadensis var. alba)
Umbrella magnolias escaped from Emily Dickinson’s garden challenge the meaning of “native.”
How
Want to find great plants native your location? These are the national databases I find most helpful.
NWF.org/NativePlantFinder: Find plant genuses ranked by number of moth and butterflies they host in your county; click on the genus to see species native to your county.
Wildflower.org: Use combination search to find plants native to your state that meet the characteristics you want.
BONAP.net: Search genus to see native range maps by county and state.
In BONAP range maps, dark green indicates native to state. Light green indicates native to county.
Wow!
We often see masses of one species of plant in nature — ferns in the damp understory of an eastern forest or rabbitbrush in the high western desert, for example. Wildflowers seem to grow this way in the Rocky Mountains. Wouldn’t masses of Rocky Mountain pentstemon and goldenrod look great in my reader’s home garden?
Left, Rocky Mountain penstemon; right, Rocky Mountain goldenrod
Related Resources
Curious how Emily Dickinson’s magnolias are challenging the meaning of native? Read As World Warms, How Do We Decide When a Plant is Native?
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