Know thine enemy: Oxalis sp., or wood sorrel

Continuing in my quest to learn my weeds, I am getting better acquainted with the most prolific of my weeds, Oxalis stricta, or wood sorrel.

Oxalis stricta

Copyright © 2005 by Robbin Moran, [ref. DOL15341].

This one is so common it’s almost difficult to see. It has a shallow taproot, but its extensive rhizome system also has lots of fibrous roots to support it. And those rhizomes go everywhere.

Unlike the other weeds I’ve examined to date, this one is a perennial. It also is apparently difficult to control with herbicides, not that I like to go that route. So the best approach to controlling it seems to be to dig it up, taproot, rhizomes, and all, and mulch heavily after digging to prevent seeds from germinating.

Growing up, we called almost anything with a three-part (tripartite–another Scrabble word) leaf a “clover.” But clover is a different plant from wood sorrel. How to tell the difference?

Oxalis leaves are heart or spade-shaped and partly folded. Their leaf margins are smooth. Clovers, on the other hand, have oval-shaped leaves with finely serrated margins and prominent veins. Oxalis species have five-petaled yellow flowers at maturity.

Red clover

Red clover (Trifolium pratense) by masaki ikeda, 22 May 2010, via Wikipedia and Creative Commons 3.0 http://creativecommons.org/licenses/by-sa/3.0/deed.en

Oxalis corniculata, or creeping woodsorrel, is a related perennial weed that grows low to the ground and roots where it establishes ground contact. Its leaves, shaped like other Oxalis species, fold downward in intense sunlight. When removing this weed, take care to dig the whole plant. If portions of the taproot or stolons are left in the ground, the plant can quickly reestablish.

Know thine enemy: Three-seeded mercury

Finally, I know who this fellow is, sort of. Acalypha…somebody, probably rhomboidea, commonly known as three-seeded mercury. He and his brothers are everywhere in my garden.

three-seeded mercury, Acalypha virginica

This annual member of the Euphorbiaceae family starts as a thin, erect reddish stem with narrow leaves, about an inch to an inch and a half long, arranged opposite along the stem. As it grows, it branches, and leaves are arranged alternately. Here is where my ignorance of botany is exposed:There appear to be small yellow flowers at the leaf axils, but those yellowish bits I see could be bracts, or technically it might be an inflorescence …anyway, if you care to read details about the plant’s structure, you can read the description from the University of Guelph extension, or the Wikipedia site. For me, right now, I know I’m fairly close to identifying the plant.

This summer annual weed is not a nuisance, except that there’s a lot of it in my garden. It doesn’t reseed aggressively like hairy bittercress and it’s not difficult to eradicate. Despite the taproot, the plants are easy to pull. They are also said to be browsed by deer (not if there are phlox and hosta to eat, they’re not).

three seeded mercury acalypha virginica

According to the Southern Living Garden Problem Solver, which may or may not have misclassified this as Acalypha virginica (my plant definitely doesn’t look like the one shown by Illinois Wildflowers.info), many insects love to feed on the leaves. Thus, my sample, with its raggedy, chewn leaves should be pretty typical.

The seeds are supposed to be choice food for mourning doves, whom I would gladly welcome to my garden because I love their call. The buffet is open!

WebRep
currentVote
noRating
noWeight