It’s the No. 1 question of the spring season in Rolla. Although there are plenty of other winter annuals invading lawns and gardens this spring, the top three have been Common Chickweed, Purple Deadnettle and Henbit.
And yet another example of the effects of last year’s drought. Many lawns in the area, which had previously been thick with grass, died back due to the drought causing more bare patches in lawns to receive more sunlight.
This occurred at the opportune time for annual broadleaf weeds such as chickweed and henbit to germinate and get established last fall and early winter.
Once sprouted and established, those weeds bolted this spring producing a flush of growth which seemed to carpet every lawn and garden in the city.
Common Chickweed (Stellaria media), Henbit (Lamium amplexicaule), and Purple Deadnettle (Lamium purpureum) are all annual broadleaf weeds which germinate in the fall and complete their life cycle in the spring when they go to seed.
By the time the temperatures start to rise, these weeds will gradually diminish in the lawns around Rolla. Already, when I went to get photos for this article, chickweed and henbit were starting to decline along the Deible Loop Trail.
“How do you get rid of winter annual broadleaf weeds in your lawn?”
Recently the MU-Extension horticulture specialists from around the state discussed the control and preventative measures for these winter annuals which are plaguing not just Phelps County, but the entire state of Missouri. The conclusion was as follows.
Since most of the winter annuals such as chickweed have already gone to seed and completed their life cycle, the best immediate solution for this year is to continue to mow your lawns at an appropriate height or hand rake, hoe or till under the weeds in your gardens. The plants thrive in cool weather and will diminish as temperatures begin to get warmer.
The best way to prevent a population explosion of winter annuals occurring next year is to re-establish a thick lawn by this coming fall.
Once the lawn is establish, the carpet of grass will provide too much competition for the winter annuals to invade at such high levels. Keeping your lawn healthy with adequate timely fertilizer and watering during dry spells will improve a turf grass stand this spring, summer and fall and will aid in weed control.
With any weed pest, a combination of multiple methods of control work best. I have already mentioned a mechanical method of proper mowing or ripping the plants out with a garden rake, and a cultural control method of re-establishing a thick turf before this fall.
The final recommendation would be to use a pre-emergent herbicide, such as Gallery, one that prevents the weed seeds from germinating. Timing is everything with a pre-emergent herbicide. After seeds sprout, the herbicide has no effect on the plants. Remove as much grass debris as possible, and apply the pre-emergent herbicides in late September. It will prevent the weeds from getting a hold on your lawn during the fall and winter season.
Page 2 of 2 - For more information on weed control in lawns, fact sheets from the MU-Extension on home lawn weed control guide number G6750 can be found at www.extension.missouri.edu.