Issue 10, June 25, 2012

Toothed Spurge--the Un-Impatiens

Have you ever let a young plant grow only to later learn that you shouldn't have? I think many of us have been guilty of this. Let's go one step farther. Have you ever transplanted a mystery plant only to later realize that it was not what you thought it was? Well I have and I probably shouldn't admit that openly to the public, but I'm a firm believer in laughing at yourself and learning from your mistakes. Perhaps you can learn a little something from this too.

A couple of years ago, I spotted a few young plants growing in one of my flower beds. I thought surely these "impatiens" had seeded themselves in, yet I didn't quite remember planting impatiens there the previous summer. Still, I decided these young flowers should live but in another, shadier location. I spent the better part of an hour one hot summer afternoon transplanting these little seedlings. Then after a few weeks, I noticed that these were the oddest looking impatiens I'd ever seen. The leaves had grown longer than they should have and there were these prominent, round seed capsules at the top center of the plant. Upon breaking one stem, I noticed a milky sap. When I finally stopped laughing at my own stupidity, I did a little investigating and learned that my plants were not impatiens but instead toothed spurges (Euphorbia dentata).

Toothed spurge is not a weed I learned about in any of my college weeds classes and it's not even included in some of my tried and true weed ID books, yet it is known to occur across most of the U.S. including all of Illinois. It is an annual that grows erect, spreading, and branched from 8 to 24 inches tall. It is typically found in waste areas and roadsides but can be found in field crops, and apparently flower beds. The leaves are opposite but the lower ones can be alternate on the stem. The leaves are ½ to 3 inches long and ovate to lance-shaped. They are typically hairy with coarsely toothed margins. In my defense, the toothed margin becomes more sharply cut (pronounced) with maturity.

The flowers, which lack petals, are small, occurring in clusters at the ends of shoots and branches. Seed capsules follow soon after the flowers. They are smooth, green, and 3-celled (each with 1 seed). Spurges are noted for having a white, milky juice throughout all plant parts, and toothed spurge is no exception.

Another name for this plant is wild poinsettia. Perhaps I would feel better if I had mistaken it for a poinsettia. This serves as a gentle reminder that proper weed identification is important, anything can pop up in your landscapes, and we all have much to learn or at least I do.

Check here for more pictures of toothed spurge. (Michelle Wiesbrook)

Michelle Wiesbrook

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