What is this prickly thing in my yard?

Published 7:36 pm Thursday, August 16, 2018

Typically, this “pointed” question boils down to two weeds in eastern North Carolina lawns. This is going to be either lawn burrweed or sandbur. How do you know which is causing the discomfort in your yard?

Lawn burrweed, also known as spurweed (Soliva sessilis), can be aggravating, to say the least. This is a winter annual weed that grows in turfgrass. Being a winter annual, burrweed germinates in the fall when the seasons begin to change. Many winter annuals will begin germinating the first or second week of September and continue throughout fall into the winter season. It has a low-growing or prostrate growth habitat with inconspicuous flowers. These flowers produce seeds with very sharp spines that stick in bare feet and pets’ paws, causing pain. Once the seeds are noticed in late April to mid-May it is too late to treat for lawn burweed, because this annual plant is on its way out for the season.

Sandbur (Cenchrus incertus) is another frequent flyer in our coastal and shoreline communities that causes summertime fun interruptions. Sandbur has an upright growth pattern with a spiked seed head full of thorny seeds. Unlike lawn burrweed, this is a summer annual which means it germinates in the early spring season, throughout February and March. The plant will seed out in late July throughout August before dying out for the winter. Again, once the seeds are noticed, it is too late to do much about this issue through chemical means.

One little trick you might try is to use an old blanket — the kind that it seems everything “sticks” to — lay it out on the lawn with a few bricks or cinder blocks on top, then drag or pull it through the lawn by hand or with a riding lawn mower. If you have a lawn sweeper this would work, as well, to get as many of the seeds up as possible. Maintaining a healthy stand of warm-season grass is your first and best defense against many weeds! Using a timely application of a pre-emergent herbicide that is correct for your grass type will give you the best shot at eradicating these nuisance weeds from your home lawn. A pre-emergent herbicide will give you approximately three months of protection from annual weed germination. If you have sandbur, the application time for pre-emergent  herbicide is between Jan. 1 and Feb. 15; for lawn burweed, the application time is the beginning of September until the beginning of October. A follow-up, post-emergent herbicide application may be necessary in the spring but only after green-up of your warm season grass, typically in mid-May. As always, make certain the chemistry you are using is right for your turf type and follow the label: the label is the law!

If you have a question to submit, please email to Gene Fox at gene_fox@ncsu.edu. If you are having trouble with growing in your home landscape, call the Beaufort County Cooperative Extension office and speak to an Extension master gardener volunteer, Mondays and Wednesdays between 10 a.m. and noon at 252-946-0111. EMGV’s will also be at the Washington Farmers’ Market on Saturdays throughout September to answer questions and diagnose problems. Learn more on Facebook through the Blacklands Area Horticulture page or visit the Extension Office located at 155 Airport Road.

Gene Fox is the area agriculture and consumer horticulture agent for Beaufort, Hyde, Tyrrell and Washington counties.