weed wars: hedge bindweed and spotted spurge
NOT ALL WEEDS ARE ALIENS, and at the moment I’m actually doing battle with two that are technically native American plants, but very unwelcome nonetheless. I’m currently uninviting spotted spurge (top right), a low-growing Euphorbia relative that’s technically Euphorbia maculata or Chamaesyce maculata, depending who you ask. At the other extreme of height, I’m asking hedge bindweed (Calystegia sepium, formerly classified as a Convolvulus, top left) to please let go its counterclockwise twining grasp on some shrubs and ornamental grasses here. Out, out damn weeds!
SPOTTED SPURGE, or Euphorbia maculata, is an annual that waits until the weather warms to really get going here in early summer, when its left-behind, prior-year seeds germinate. In my garden it loves the patio’s cozy cracks and crevices.
Dig it, roots and all as soon as it shows up, but if you are inclined to getting dermatitis from the latex sap of euphorbias, be especially mindful and wear gloves. Always be careful with latex-filled plants not to touch your mouth or eyes, whether you have ever had a rash or not! I use a hori-hori, or Japanese weeding knife, to get it out from between the pavers, but an old kitchen knife will do.
The seeds need light to germinate, so a heavy layer of mulch would work to help stop this one—though not on my crack-and-crevice issue, of course. (Can you picture me spooning mulch onto every crevice?)
Each year my crop has more leaves with characteristic reddish-brown spots early in the season than it does later, and there are related species that have no spots at all, but spotted spurge my issue certainly is. It came in on a nursery pot, a common way to get this weed in your garden, so be more careful than I was.
A final fact: Spotted spurge is apparently fatal to grazing sheep (though apparently it’s not effective on rabbits and woodchucks–or at least my local ones refuse to eat it!). More on spotted spurge and its cousins, from UC-Davis.
THIS WAS A NEW ONE on me this year, a perennial climber with impressive towering ambitions. When I first saw it I thought it was field bindweed, a.k.a. wild morning glory (Convolvulus arvensis). But then I noticed differences in scale, and more. The leaves are slightly different in shape than field bindweed’s, and the flowers are a little larger, but that can be hard to feel confident about unless you can compare them side-by-side.
The easiest ways to tell one from the other, I think: hedge bindweed’s flowers have one large bracht at their bases. In field bindweed (which by the way seems happy to grow along the ground, not just climb) there are two smaller brachts, lower down on the stem, behind the flower. The vintage illustrations I merged, above, compare the two—with field bindweed on the left and hedge bindweed on the right (a photo of a hedge bindweed leaf is just below). More comparison here.
I can’t get into the bed of tall ornamental grasses and twig willows right now to dig out the bindweed’s root system, so I’m trying an alternate suggestion from Teri Dunn Chace’s new book: stripping off all the foliage, again and again, to weaken the vine, meantime removing all the flowers to prevent seeds from being set. But I know I must go back for those roots this fall.
more weed wisdom
- Clearweed, or Pilea pumila (photo just above the previous section)
- A weed I planted, Houttuynia or chameleon plant
- Garlic mustard, Alliaria petiolata
- Commelina and Galinsoga, two more opponents here
- How to ID your weeds—links to online guides
- Smothering weeds with cardboard and newspaper
- Piling on the mulch for weed suppression and control
(Illustrations used with permission of USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. “An illustrated flora of the northern United States, Canada and the British Possessions.” 3 vols. Charles Scribner’s Sons, New York. Vol. 3: 47.)