As our brief cool spells end and seeds start sprouting, now is the best time to get ahead of weeds. When the warm weather weeds are small, they can often be successfully controlled with herbicides. Ignoring them now results in difficult-to-eradicate patches and more seeds for next year.

Let’s talk weed war basics. There are two types of weed killers: pre-emergent and post-emergent. The first line of weed defense this time of year is a pre-emergent herbicide. This keeps the weed seed from sprouting at all, stopping the problem before emerges. Conversely, post-emergent herbicides kill the plant after it has sprouted. Even those work best when weeds are small, however. Once the weed gets big and strong, it can be hard to kill – especially if it’s in the middle of a lot of other plants that you don’t want to harm, such as in a lawn or flower bed.

Surprisingly, not every herbicide works on all weeds. Even glyphosate, the ingredient in the popular Roundup™ spray, doesn’t kill every weed. I sprayed it on a problem patch and it killed almost everything – leaving a clear path for my nemesis, Artillery Weed, to take over. So the first rule is: know your weed before you try to kill it, so you can pick the right method. If you are not sure, take a sample to your local UF/IFAS Extension County office for help with identification .

Many herbicides are labeled for “grassy weeds” or “broadleaf weeds.” If the weed has long, narrow leaves and looks like grass (e.g. sedge, crabgrass), it’s a grassy weed. If it has broader leaves (e.g. dollarweed, spurge), it’s a broadleaf weed. Pretty simple. Still, there are some exceptions for herbicide effectiveness, so try to identify the specific weed and check the label.

Different people have different attitudes about turfgrass. Personally, if it’s green and looks somewhat like grass when it’s neatly mowed, I don’t stress about it. But many people insist on a pristine expanse of emerald-green lawn that could host a professional croquet club. No matter your turfgrass goals, the best weed prevention is a thick, healthy lawn. Mow at the right height for your type of grass, and apply recommended fertilizers and pest control. The Extension Center has guidelines for St. Augustine, Bahaia, Zoysia, and more – click here for more info or stop by your local UF/IFAS Extension County office for advice.

Most lawn weed-and-feed mixes contain both pre- and post-emergent herbicides. Check the label to see if (1) it’s safe for your grass type and (2) it works on your weeds. Also, check the conditions for when it should be applied – many herbicides will kill your grass if they are applied when the weather is too hot. Lastly, if your lawn has disappeared and all you have are weeds, kill the weeds, solarize to kill the seeds, and then resod.

In landscape beds, the best way to prevent weeds is to mulch. Pine bark, pine straw, and wood chips are all good. Apply to a depth of at least two inches. Avoid shredded mulch as it holds too much moisture, encouraging seed germination. Rubber mulch can be used for walkways and playgrounds, but isn’t ideal around plants. Don’t use rubber near sparks (including discarded cigarettes) as it is flammable.

Once you know your weed, the table below recommends a plan of attack. For larger weeds especially, the best approach is often hand-pulling (this is a good time to get to know some kids in the neighborhood who need pocket money), then follow up with a pre-emergent to take care of lingering seeds. I’ve found that persistence pays off – hand weed regularly for a year, use pre-emergents, and you will see greatly reduced or eliminated populations next year. You can win the weed war!

This blog post was written by UF/IFAS Extension Orange County Master Gardener, Mary Ann Pigora, class of 2017. The UF IFAS Extension Orange County Master Gardener Volunteers play a crucial role in the outreach of UF IFAS Extension.

1