I lived in West Palm for 5 years and also tackled sand spurs. When I first encountered them, I couldn't believe nature could be so mean. St. Augustine is not much competition for them. The best way to combat them is to mow the lawn short during the cooler months, and allow it to get real tall during the wet summer. When you lower the mower blades in Oct., the seed stalks get cut because they have been reaching for the light.

Thank you for that suggestion. I mow my yard at 3" currently. Adding another inch for the remainder of the summer shouldn't hurt too much.

Well, last week I set my blade to 4". This week, I have unexpected fruit. It is both fortunate and unfortunate however. Thanks to the sandspurs trying to growing upward through the grass, they are a lot easier to spot and pull. However, I have learned that I had not put nearly as large a dent in their population as I had thought. The jerks appear to have been spreading under the bermuda and then rising upward. Really stealth-like and sneaky. But they didn't adapt their tactics too well to the new mower height and now I'm seeing them.

However, I have been mulling over this idea of letting them grow upward and then mowing low in October. Won't this just spread the seeds around the yard more? Or does this tactic require the use of a bagger mower to collect the seeds as they're cut? If so, I may have to borrow someone's since mine is a mulching deck.

Don't let them go to seed! One year to seed, 7 years to weed. If your grass is thick enough, and not sparse, you can alternate the mowing. Or mow low every other week, skipping a week. The thing is to allow them to put their energy into flowers and then whack them. They will starve.

By 'seeds' I mean the briars. Are the briars the flowers? Well, I guess they would have to be. I have found them in various stages from just emerging from their 'sleeve' of grass to fully extended, but I have never seen anything else that looks like a flower. At which point do they become viable seeds?