Getting to Know Your Weeds...Sandspur

This is generally the time of year we notice sandspur problems in our pastures and hayfields. Maybe they were there last year too and they're still a problem. Sandspur can be aggravating for us to control and even more aggravating to a grazing animal. 

Sandspur is an annual grass weed and tends to grow well in fairly sandy soils. It must drop viable seed to reproduce. There is more than one type of sandspur – Southern, longspine and field sandspur can be found in our part of the country. Sandspur can tolerate poor conditions and is easy to spread via grazing or haying. At the early stages, sandspur can be a challenge to identify against other grasses. There are a few characteristics that can help you with identification early in its growth cycle. Sandspur has a fibrous root system and plants tend to be a lighter green than many other grasses.

Sandspur seedling (Photo courtesy Virginia Tech).

The leaves have several identifying characteristics. First, leaves tend to feel rough, compared to grasses such as ryegrass. Next, leaves appear flat but are folded when budding. Third, leaves usually have a raised midvein and have few or no hairs. The ligule is an outgrowth from the base of the grass blade and is very important in identification. Here's a photo of a ligule on a sandspur, which is only a fringe of hairs. Ligules on other grasses may be a thin membrane or may be non-existent.

Sandspur ligule is a fringe of fine hair, about 1 mm long. Photo courtesy Virginia Tech.

Sandspur stems can stand straight or spread, splaying outward. When you run your thumb over the stem it will feel flat, not well rounded like many other grasses. There can be many branches off the stem as well, particularly as the plant matures.

Another identifying characteristic for grasses is the presence or size of auricles. Auricles are projections at the joint of the leaf blade and sheath. Auricles are absent on sandspur.

Diagram explaining parts of the plant for identification purposes. Diagram courtesy University of Georgia.

The sandspur’s tell-tale burs are a common sight once the plant is maturing.

Sandspur producing seedheads or burs. Photo courtesy Virginia Tech.

Once you know you have sandspur, how do you control it? First, contact your local Extension Agent for herbicide options. They can give you information on rates, restrictions, and check products that will work at different plant growth stages. Second, avoid grazing the area that is infected to avoid injury to horses and livestock but to also avoid moving seed to a clean area. Third, when mowing, mow clean areas first before moving to infected areas. Clean equipment after mowing infected areas. Mowing can give temporary control to reduce potential for seedhead development but as plants are mown they typically produce seedheads closer to the ground to compensate. Controlling sandspur may take more than one season to accomplish particularly if seeds have banked in the soil and sandspur has been established for years. With multiple approaches to this weed, sandspur can be controlled.