Grassburs are the weed that makes you stop mid-step and pull spines out of your foot.
They’re also called sandburs or stickers. Here’s how they get in, and how to push them out.
What grassburs are
Grassbur is a grassy weed. Texas A&M AgriLife Extension says the burs are painful on contact. They get carried around by animals, clothing, tires and lawn equipment.
Each bur holds one to three seeds. The seeds wait until the soil is warm enough to sprout.
Most grassburs act like a summer annual. AgriLife says some can come back as perennials. Those green up earlier, make seed earlier, and are harder to control.
How to spot them early
Look where grassburs grew last year. Seedlings often come up in the same spots, near old plants and burs.
AgriLife says seedlings usually have hairless leaves and sheathed stems. As they grow, the stems flatten and often turn maroon to purple at the base.
To spot the perennial kind, check in winter. Slice open the crown of a dead plant where the roots meet the foliage. Green tissue means it’s still alive.
Why you have them
Grassburs like sandy, dry, low-fertility soil. They aren’t limited to it, though.
Thin turf is the real opening. Bare or weak patches give seeds room. A thick, well-watered lawn gives them a hard time.
North Texas lawns get thin for common reasons:
- Too much shade
- Compacted clay that drains poorly
- Drought stress
- Mowing too low
- Too little fertilizer
Keep new burs from coming in
Seeds travel. They stick to pets, shoes, tires and mowers.
Check your dog after walks. Brush off shoes and equipment before they cross into the lawn. It won’t stop every seed, but it cuts the supply.
Why mowing alone fails
Mowing trims the plant. It does nothing about the seeds in the soil.
Seedlings tiller early, so they compete well against nearby turf. AgriLife’s memo says a seed head forms in about 7 to 13 weeks. And mowers can carry burs from one spot to the next.
Mowing at the right height for your grass helps. It supports thick turf. It just isn’t a control by itself.
Prevention timing
Prevention is the strongest tool. AgriLife says a pre-emergent is crucial once the turf is established.
Seeds start to sprout when the average daily soil temperature reaches about 52°F. AgriLife says germination can peak around 75°F.
The sources differ on the date. A 2025 AgriLife memo calls February the ideal time to start. An older Extension piece written for Dallas says to apply by April 1 in North Texas. The weather that year decides where in that range you land.
Two sprouting seasons
Grassburs sprout in spring and again in fall. AgriLife says split applications matter, because one application won’t cover both seasons.
For heavy infestations, the older Extension piece recommends repeating the pre-emergent about every six weeks through September. Your label sets the real interval.
Water it in
AgriLife says the product needs at least a half inch of rain or irrigation before the soil enters the sprouting window. Not enough water is a leading reason pre-emergents fail.
What about the ones already up?
A pre-emergent can’t kill grassburs that have already sprouted. For those, AgriLife points to hand removal or a post-emergent herbicide.
Wear thick gloves and bag the burs. Don’t leave them on the lawn.
Selective post-emergent options are limited. They depend on your grass type, and some only suppress the weed. That is why the product has to be labeled for your turf.
Thicken the turf
Thick turf is how you stop them for good. AgriLife says the foundation for control is a healthy stand.
- Mow at the right height for your grass type.
- Water deeply and not too often.
- Fertilize on a schedule that fits your grass.
- Fix compaction and drainage problems.
- Fill in bare spots.
When to call a pro
Call a licensed applicator if:
- Grassburs come back every year.
- The infestation is heavy.
- You think you have the perennial kind.
- You’re not sure what your product can be used on.
Follow the product label on any application. Keep kids and pets off until it has dried, as the label directs.
Want it handled?
Timing, soil temperature and product choice decide whether grassburs get stopped. Green Ops’ weed control and fertilization program is handled by a licensed applicator who picks a product labeled for your grass type. Ask for a free quote in Mansfield, Tarrant and Johnson counties.