I don't know how many people have been following the debate carried on between me and my friend Nif in the comments on the "Beautiful weeds" post, but the gist of it was something like this: I claimed that dandelions and purple deadnettles (Lamium purpureum) weren't really weeds in my yard, because I didn't object to their presence. Nif argued that I should object to their presence, because they were invasive and messed up local ecosystems. I argued in turn that even if these were aggressive non-native plants, it was less destructive to let them grow than to try to eliminate them (which might require toxic chemicals) and then replace them with plants that had to be cultivated (which might require lots of water and fertilizer). At that point, the discussion kind of petered out.
Now, naturally, Nif and I would agree that the best option of all would be a native plant that flourishes without assistance in the environment of my yard. But unfortunately, there don't seem to be any plants that fit that description. To illustrate, consider the problem I've been going through trying to find a ground cover for my front yard.
My front yard, as you can see in the photo, is a little sort of boxed-in patch of grass raised up from the sidewalk. That means that in order to mow it, you have to go out back, get the mower out of the shed, haul it up a short flight of stairs into the driveway, haul it up two more stairs onto the front path, and then heft it up over the short wall that encloses the yard. Even with a lightweight little push mower like we've got, that's a nuisance. So I've been looking for some time for a simple, low-maintenance ground cover that could replace the grass. Such a ground cover would have to meet the following requirements:
1. not too tall (say, 8 inches or shorter)
2. tolerates full sun
3. can grow in clay soil
4. can handle occasional light foot traffic (we're not going to be playing soccer on it or anything, just going out from time to time to do some work on the other parts of the yard)
There are almost no plants that meet these fairly modest criteria. I've only found four: silveredge goutweed or bishop's weed, barren strawberry, moneywort or creeping jenny, and blue-star creeper. All four of these are described as invasive in at least one source I've consulted.
So in other words, either I put a potentially invasive plant down in my yard, or I'm stuck with water-guzzling, high-maintenance turfgrass. Bah!