How Well Do You Know Your Weed(s)?

By Bill Swantner, Bexar County Master Gardener

Every spring, young children carefully pull up that magical dandelion with its white head of seeds; they make a wish and blow the seeds into the wind. I don’t know that their wish came true, but the surrounding landscapes now have the possibility of weeds.

The technical definition for a “weed” is any plant that is not where you want it. So technically, a bluebonnet in a rose garden is a weed. It’s January and the only two things usually actively growing in the garden are vegetables and weeds; the former bring words of joy; the latter… well, those are different words. This series of articles will be on weeds: the unintended plant.

Controlling weeds is an ongoing challenge for all gardeners, whether you’re a weekend gardener or a full-time gardener. The temptation is to spray the weed with something… anything. But spray with what? How much? How often? There is an integrative approach to weed control, much like integrative pest control: Cultural, Mechanical, and Chemical.

Cultural Control In lawns, cultural control is having the correct grass in great soil, in the right location; watered, mowed, and fertilized correctly. Bermuda & Buffalo grass will not tolerate shade. When grown under trees, these grasses thin out and allow weeds to grow. When lawns are watered and fertilized, weeds are also being watered and fertilized. Cultural control is meeting the nutritional needs of the lawn grass to grow fully and prevent the opportunity for weeds to develop.

In gardens, cultural control begins with well amended soil. If our clay soil is broken up through the use of compost, weeds can be easily pulled. But it’s the use of mulch that is the best cultural control. Mulch can prevent the seed from reaching soil, and if the seed reaches soil, mulch can help prevent sunlight from reaching the seed. If seed takes root in mulch, it is easily removed because the roots can’t take hold in soil.

Mechanical control of weeds means to remove them physically, by hand or by tool. The best rule of thumb for the mechanical control for weeds is to catch the weeds early and often; pull them or mow them. And definitely, try to remove them before they go to seed!

Chemical control should be the last method of controlling weeds. When using chemicals, always read and follow directions. Chemicals control weeds in one of two ways: “kill everything” and target specific weeds. To target specific types of weeds, the gardener needs to know if the weed is a broadleaf, grass, or sedge.

In all cases, the earlier a weed can be treated (pulled or treated chemically) the better.