Late Summer Yellow Foxtail

We often get questions on late summer weeds in pastures, and the general comment is “where did all these weeds come from?”  The short answer is from seed. When we think about pasture or late summer hay production, we need to understand that the weeds job is to survive and produce seed. Yellow foxtail is one of the bigger summer annual weeds that can be problematic in pastures and hayfields. This blog will provide more details on how to best manage this weed in pastures and hayfields.

Yellow foxtail is very prevalent in pastures and hay fields right now. Yellow foxtail is best adapted to late summer and early fall weather conditions. It is a summer annual and germinates with optimum soil temperatures from 70 to 85^·F.

Yellow foxtail can be identified by pale to medium green and course leaf blades and a prominent midvein. It has long sparse hairs at the base of the leaf blade and sheath, with no auricles present. It will stand out as a large clump of grass.

Managing with renovation

Control of yellow foxtail is difficult in pastures and hayfields. Often this is a sign that a renovation or reseeding is necessary, especially in alfalfa fields. While herbicides are labeled for control of foxtail options are more limited in pastures and hayfields.   

When considering renovating pastures or areas with high yellow foxtail pressure, two methods can be considered. The first renovation method would include killing all vegetation with glyphosate application and reseeding with desirable grasses.  The second renovation method would involve tillage and the use of a pre-emerge herbicide.  Pre-emerge herbicides to consider include pendimethalin, trifluralin, and EPTC. Tillage is often not recommended due to erosion.

If you are renovating an alfalfa field, just remember to NOT plant alfalfa back on the same location within 18 to 24 months from a previous alfalfa field. You could still seed grass or a legume other than alfalfa.  When seeding alfalfa remember to control weeds prior to emergence since few options are available post emerge in seedling alfalfa. For more information see 2024 Guide for Weed, Disease, and Insect Management in Nebraska. https://marketplace.unl.edu/extension/ec130.html

Managing with controlled grazing or mowing

Often the most effective control method is controlled grazing or mowing.

When considering mowing, we need to accomplish this BEFORE seed set. Early season identification and scouting is important. Beware that foxtail is a summer annual and comes later in the season; therefore, some seed heads may develop even if you mowed earlier in the season.  Selective mowing is a good management strategy in pastures but less effective in hayfields. 

If you make hay from fields with high populations of yellow foxtail, be prepared for cattle to sort this hay. If you have horses, they may refuse or sort this type of hay. It is best to limit the amount consumed by horses due to possible irritation of the gums from seed heads. 

When purchasing hay, foxtail should be easy to identify in bales and always ask what cutting of hay you are buying and what month the hay was baled, as this can give you insight into what weeds to look for in hay.

Contact your local Extension field agronomist if you have any questions.