In my “More plant families” posting yesterday, I turned to two big families I’d missed in an earlier posting and then to my recollections of plants in my Columbus OH garden that were self-seeding and/or self-hybridizing: cleomes, California poppies, opium poppies, foxgloves, borage, columbines, tradescantia, nasturtiums, and then I looked at the plant families they belonged to — a project that added 8 more families to the 9 I’d looked at in the earlier posting and the two I’d looked at in my “Penstemon” posting. (If you’re counting families, the score is now 19.)
Now I want to switch my focus from the intricacies of botanical taxonomy (without abandoning the topic entirely) to the significance of self-seeding (or self-sowing), one form of invasiveness in the gardening world, one way in which plants can spread so as to take over parts of a garden. The other is vegetative spread, by division or, especially, by creeping (via underground roots or surface runners). You’ve got your seedy invasives and you’ve got your creepy invasives.
Of course, the topic goes well beyond these homey horticultural matters, to invasive plants — and animals — on a much larger scale, where invasiveness has taken on political significance of several kinds. Eventually I intend to post about a piece by Andrew Cockburn in the September 2015 Harper’s, “Weed Whackers: Monsanto, glyphosphate, and the war on invasive species”.