We are entering the home stretch of our weed series, "The Ten Most Unwanted Weeds." Only three are left but I might cover a few more if it strikes my fancy.
This next weed can be the scourge of many lawns, flowerbeds and vegetable gardens. I am talking about prostrate spurge or spotted spurge which are one and the same. The Latin name for this weed is Chamaesyce maculate, a member of the Euphorbiaceae, the spurge plant family. Another member of this family is the casterbean, both a cultivated crop in some regions as well as poisonous to animal and humans.
There are five species in this genus but only this one is a serious weed in our area. It is a summer annual, with seeds germinating in the spring and summer. Seed production from these newly-spouted plants will begin in about five weeks.
This is a prostate plant that can form larger, thick mats, smothering any other desirable low growing plants. Both stems and leaves are hairy. Plants have a long taproot. It produces tiny, nondescript pinkish flowers in clusters in the leaf axils. Seed pods are three-lobed and about 1/16 inch long. Seeds are 1/25 inch long, really tiny.
When stems are broken, a milky, sticky latex juice will ooze out. This milky substance can be irritating to some folks. Some plants have leaves with large purple spots, hence spotted surge. While others have leaves absent of these spots, hence prostrate spurge. They are still the same species.
This weed tends to grow most prolifically in weak areas of lawns and other garden areas. They can be a good indicator that something is wrong below the soil surface since they prefer poor, compacted soil. Mulching garden areas can often limit their emergence. Otherwise you should dig plants up before they produce any seed.
Chemical control can involve pre-emergent herbicides, such as Preen® or Treflan®. Otherwise you will need to resort to foliar sprays of something such as 2,4-D or glysophate (Roundup®). Just remember that gysophate herbicides kill all green things so it is not a wise choice for lawns, unless you like spotted lawns. Sprays containing 2,4-D are selective to broadleaf plants. Make sure to use a spreader-sticker, with a commercially available product or dishwashing soap (one tsp. per gallon of spray mixture).
So what are you waiting for? Get out in your gardens and find and control these and other weeds before they become a bigger problem. Until next time, enjoy the warming temperatures and the fragrance of early blooming spring flowers.
Jim Leser retired to Cedaredge in 2007 after a career with Texas A&M University Extension in entomology. He is a member of the Cedaredge Tree Board and a Colorado Master Gardener.