The New England Wild Flower Society‘s newsletter has an excellent article by Bill Cullina, NEWFS’s former Director of Horticultural Research, now at the Coastal Maine Botanical Garden. He discusses some of the complexities of the argument for using native plants, and makes the point that native plants promote diversity in all organisms living in a certain place, which itself promotes stability in the ecotone.
He introduces a couple of phrases worth remembering: one is ‘bionegative’, which applies to an invasive species (native or not) that takes over a place and diminishes biodiversity. Multiflora rose can be considered bionegative in New England, where it grows with such vigor that it eliminates almost all other plants. Bees love its pollen, and birds love its rosehips, but not much else benefits from it; the area it colonizes tend to become monoculturally static.
The other phrase, ‘biopositive’, applies to locally native species that support a large variety of organisms without being imperialist about taking over a place. Cullina discusses blueberries and huckleberries as example of biopositive plants in New England, and then lists ten other plants — what he calls “biopositive all-stars” — that merit attention.
If you’ve never read anything by Bill Cullina, this article is a good introduction to some really helpful concepts, and to his work. (He has written several books on plants, which are both fun to read and incredibly thoughtful and informative.) I am a big fan of people who think about complexity and who write well; a sense of humor makes me an even bigger fan. Bill Cullina ranks in my horticultural pantheon, and this article should be seen by anyone who has ever had to address the question “Why use native plants?”.