Every silver lining has its cloud, and with this summer's splendid rains comes not only the extreme happiness of spadefoot toads, lizards, bugs, birds and all the plants you love, but also the resurgence of every plant you don't in what seems like every place you don't want it.
Here at the Sixth Street Noxious Plant Nursery, we've spent the last two Saturdays dripping sweat while weeding our back yard and already the usual suspects are ankle-deep again. Notable among them is the tall, vaguely clover-like thing that won't come out by the roots, the spreading, fleshy thing that will (if the ground is damp and you don't yank) and the opportunistic, infant hoards of Rhus lancia and palm.
The soil around our house hasn't been disturbed much, so we don't get the stickery tumbleweed that thickly adorns recently scraped lots, and we've persecuted the Bermuda grass so viciously that it doesn't really try any more. (It's in the same state as the harvester ants, upon whom Ed declared war after they stripped the rosebush for the fifth time.) But we do have to keep an eye out in the alley, at least, for the least desired of all suburban desert plants--the puncture vine.
I've often thought that everyone who moves to Tucson ought to get a little Welcome-Wagon booklet on Bad Plants and Your Duty to Go After Them. (Among other things. There would also be advice about getting into parked cars in the summer and finding real Mexican food, plus coupons for industrial-strength moisturizer, tequila and limes.) It would contain clear photos and drawings of vegetative evil-doers like buffel grass (thrives in the desert, where it crowds out native grasses and provides fuel for fire) and desert broom (sends out clouds of cottony seeds every fall, comes up everywhere and is impossible to pull.)
Still, the worst weed of all from a nuisance point of view is puncture vine, also known as goat-head vine, Tribulus terrestris. (Many thanks to Nathan O'Meara, curator of horticulture at Tucson Botanical Gardens.) It's the plant that produces those little organic caltrops that one so often finds stuck to flat bike tires and the paws of limping dogs. (My big dog won't even try to move when he picks one up: He stops dead with the wounded foot lifted and look of horror on his furry face. As tough as a young mule in every other respect, he loves and needs and worries about those paws.) You can also sometimes find goat-heads stuck to the soles of cheap flip-flops worn by sobbing children. Stepping on one is exactly like stepping on a tack.
The spikes are there to disperse the plant's genes as widely as possible, and, boy, was that a good plan. You can find the flat, spreading plant in virtually any alley or vacant lot in Tucson, where it starts putting out pretty little yellow flowers that turn into four-pointed tacks almost immediately after germination.
And when you do find it you pull it up, carefully, so you don't get poked, and toss it in the nearest dumpster. It usually comes up root and all with just enough resistance to make ripping it out satisfying.
Here's how to spot it so that you can begin to perform this vital civic duty:
Like many other desert regulars, puncture vine has pairs of tiny, oval opposing leaves. When very young it grows upward, but once it's well established it sprawls out, forming a ground-hugging dull-green circle on the bare, dusty ground it prefers. As I already mentioned, it puts out small yellow flowers when it's gotten any water at all. (The sonsabitches thrive right through the hottest part of the year in full sun.) Where there is one, there will be others. If you have any doubt about what you're looking at, touch it. Gently. The neatly camouflaged goat-heads will be everywhere.
Puncture vine is easily confused with a smaller, less robust spreading weed with red stems which is harmless and which you don't want to bother with. You want the murderous, yellow-stemmed individual that you can almost see growing.
Know your enemy: That knowledge is what the Tucson Weekly is all about.