Gold Coast Gardener

February 26, 2006

By Gene Joyner, Extension Agent
Palm Beach County Cooperative Extension Service

Pretty much most of our winter temperatures now are history and we should have consistent warm temperatures that encourage plants to wake up and start their strong spring growth. Some types of plants though that are growing strongly aren’t appreciated and those are weeds. Weeds seem to be everywhere in the landscape and no matter how hard you try it’s virtually impossible to keep a landscape 100% weed free throughout the year.

Weeds come in hundreds of different species and most come from seeds which are wind borne so you never know when they are going to be arriving on the next windy day. Weeds can be divided into several groups, warm season and cool season, and also grasses, sedges, or broadleaf types. Some people have the same types of weeds consistently giving them a lot of problems, while others may have one type of weed this month and then a month or two later a different type of weed seems to be the most dominant.

To control weeds in the landscape though there are a number of steps that are important to be followed throughout the year. The first one is to not leave any bare or open ground anywhere in the landscape if possible. Weed seeds germinate quickly in these areas and some weeds can reproduce and be producing new seeds within a two week period so it won’t take long for a small patch to become a large patch and overtake the rest of the landscape.

Use mulches wherever possible in the landscape to cover bare ground and make it harder for weed seeds to germinate. You can use either natural wood type mulches or artificial mulches like ground up automobile tires, ground cloth type products, or even plastic. If you’re using mulches, particularly natural mulches they need to be at least 3 inches deep to be effective. They compact down rather quickly and if they are too thin to start with cracks will develop, weed seeds can fall through the cracks and still get to the soil.

One way of combating weeds in areas too is to put a lot of ground covers or vegetation so that there’s too much competition for weeds to get a good foothold. In turfgrass areas weeds can always be a problem, but if the turfgrass is mowed, fertilized and watered properly weed invasion will be minimal. If you have to choose a grass which is better for weeds and can outcompete them, St. Augustine type grasses are better than bahia which is more open growing and less tolerant of weed invasion.

There are weed control products that can be applied to turfgrass and these are generally applied seasonally. Most are applied in the early spring for best results, but you can also apply them again in the fall around late October, November and early December. Most of the selective type weed killers used on turfgrass work against specific weeds so don’t expect to apply a product and have every single weed killed. There’s no magic product yet for that that won’t injure the good grass.

In flower beds you can use spot treatment weed products such as Roundup or similar herbicides, but be careful about getting them on desirable plants because that will result in damage. For very tiny areas the old tried and true method of hand pulling works very well, too, and this way you don’t have to apply any chemicals and you’re sure that you’ve gotten the weed out.

If you have questions about weed control this time of year in the landscape and want some helpful advice, contact the Palm Beach County Extension office. Dial 233-1750 in the north and central county area or 276-1260 in the south county area.