In the group of abused landscape terms, Native plants should file a restraining order against most of us in the green industry. In the parlance of our greenspeak, we stretch and deform the phrase like silly putty to make a point or to fit the sensibilities of our audience. It's particularly amusing to watch two green industry professionals use the term as a kind of litmus test, dodging and parrying like two strangers at a party discussing philosophy or religion. And just as terms such as "spirituality" and "solipsism" have largely been bleached of any specific meaning, the phrase Native plants has been assigned its own identity crisis.
I make this observation without any antipathy for the use of native plants in the landscape. In fact, using native plants is a fantastic way to reduce water, fertilizer and pesticide inputs. Plants that grow naturally in a geographic area are adapted to the ambient rainfall, soil type and zonal nuances of a specific region and generally don't need the life support system that makes up such a large percentage of our billable work in the green industry. But what is the criteria for defining a plant as being native? Is it a plant that once happily grew where your house now sits before all the top soil was scraped off and sold? A plant that's native to North America? Or is it a one gallon something or another at the grocery store that's marketed with a crossed out water drop and has a link to the Audubon society?
In the early 90's I worked as a wildland firefighter, initially on a hand crew and later as a first response helitack repeller in central Idaho. In the tiny window between the cooling ash of summer's fires and autumn's early mountain snowfall, we were given the job of preventing erosion in the recently burned areas. Massive sediment delivery into riparian areas can be devastating for fish habitat so our job was to cut down the burnt remains of trees and install them horizontally on the steep mountain slopes in an effort to temporarily mitigate erosion.
The longer term solution, re vegetation in these fire affected areas, is remarkably sophisticated and serves as an example of a particularly strict version of what Native plants means. Restoring an area to pre-fire condition means replanting with varieties that are as genetically as close as possible to the original plants. Calling a nursery in California and having two thousand one gallon Pinus contorta delivered to central Idaho is like wiping out all the Smiths in southwest Boise and replacing them with half the Smiths in South Bend, Indiana. There may be some distant relationship, but the unique qualities that defined the Smiths in Boise can't be replicated by the new comers. Broad genetic variation within a species is the first line of defense against extinction. Government agencies and private firms carefully collect seeds and propagate plants in an effort to maintain the unique genetic qualities of local, native plants.
Writing this, I'm looking out at our backyard and witnessing the beautiful collapse of the season. The gorgeous display of fall color from our very non-native trees peaked about a week and a half ago and I see the landscape slipping back into the monochromatic gray that defines our winter in southern Idaho. I try to imagine what our acre looked like before wagons began clunking down the Oregon trail a few miles away from our home. It's an image that's not too difficult to conjure as a short trip south will take you into an endless repeating motif of sage, bitterbrush and rabbitbrush. I'm not immune to the stark beauty of the high plains desert, but this natural landscape has a face that only a Minimalist, an ecologist or a chukar hunter can completely love. In all fairness, we're told this area was also covered in large clumping grasses before overgrazing, yet taken as a whole, I'm pretty sure that I don't want to return my backyard into jack rabbit habitat.
The truth is, in Boise our options are pretty limited if we try to adhere to a strict definition of what constitutes a native plant. Even the tough-as-nails Celtis occidentalis, one of Boise's few true native trees, can only be found in limited areas naturally where, in a convergence of botany and geology, large sandstone or granite boulders collect and concentrate water for the trees. We just have to face it: if the Amazon basin represents one of the most biodiverse places on Earth, we sit somewhere on the other side of the spectrum.
The arborist/science major side of me likes the idea of returning a piece of land back to its former condition, but the artist side stubbornly refuses to have his design options so cruelly curtailed. As is usually the case though, I think the answer lies outside of the argument. While two plant geeks might endlessly debate the relative merits of Chrysothamnus nauseosus (incidentally the most accurate scientific name for a plant) versus Ceanothus velutinus, the truth is that the true culprit in most landscape installation is turf grass. Planting most anything else will generally result in water savings and a decrease in the overall need for chemical input. I was once chided by a Horticulturalist friend for having a clump of bamboo (Phyllostachys mannii) next to our house in the front yard. I was compelled to point out that this particular clump of bamboo, known for its drought and cold hardiness, was surviving on very little supplemental irrigation; a point I couldn't make about the 1000 square foot swath of turf in front of the house.
In my own designs I tend to use a hybrid approach, using true local native plants intermingled with non-native, non-invasive & drought tolerant varieties. While there will always be a place for restoring original, native habit- driving through an average neighborhood I'm struck by just how much basic work still needs to be done to improve most landscape designs (enter token "sustainability" Meta tag here) . I've watched landscapers install turf against concrete on a south facing aspect and blame billbugs on the visible heat stress (and then charge the client for the chemical "solution"). The discussion of what constitutes a Native plant is largely academic in nature compared to the many obvious steps we can take to make today's landscapes less dependent on a constant life support system of fluid and chemicals.