Controlling Weeds

How do you control weeds in the garden? Dig 'em? Spray 'em? Mulch 'em? This page gives you some suggestions on whatever methods you choose. If you choose to use chemicals, use the right one for the job. I can't tell you how many times I've seen people use Roundup to kill weeds in a lawn. Well, it says it's a weed and grass killer, and I wanted to kill weeds. Well, I mixed it real weak so it would just kill the weeds and not the lawn. Well, well, well.

  Dig 'em! Mulch 'em!

Do it the old fashioned way. Dig and cultivate the soil. Add organic compost too. You will create a rich and friable soil this way, and you will be rewarded with healthy plants in the bargain.

Use organic compost of some kind as a mulch (top dressing) in your planting areas. A layer of two inches or more will suppress weeds and keep plant roots cool and moist by slowing evaporation from the soil. Retard weeds and conserve water in one operation.

Another way to prevent weeds by covering the ground is to use plastic or permeable landscape cloth covered with rocks or wood chips. I recommend river rock or shredded wood for its natural look. Shredded wood may be available from a local recycling facility.

Use a dandelion digger or other weeding tool to remove weeds from the lawn. This is certainly a good way to remove a few weeds. But this method won't work on a very weedy lawn. Keep your lawn thick and green and healthy. Weeds can't compete with a well cared-for lawn.

  Caution!

Please read the label on all garden chemicals, and follow the instructions precisely. Use only on plants that are indicated on the label to control pest indicated on the label. Mix chemicals exactly as instructed on the label. More is not better. And please be sure to follow all safety precautions to the letter.

  Herbicides for Lawns

Controlling weeds in lawns requires a defensive and an offensive plan. Use a pre-emergence herbicide twice a year. Apply in February to prevent crabgrass and spurge in the summer. Apply in September to prevent Poa annua (annual bluegrass) in the winter. These products are usually combined with fertilizer so that you are fertilizing and preventing weeds at the same time. There is a wide range of active chemicals used in these products. Check the label to see what weeds are prevented. All products are not the same.

Do you have weeds already? Let's examine the post-emergence herbicides available today.

Trimec

Trimec is a combination of 3 chemicals that kill broadleaf weeds in grass lawns. Trimec is found in most weed-n-feed products. Use caution with weed-n-feed applications. They will damage shrubs if the chemical gets on their foliage. There is another danger. One of the ingredients in Trimec is Dicamba, which is absorbed through roots. It can be absorbed by trees and shrubs that have roots under the turf. It will damage these plants if enough chemical is absorbed. I prefer to spot spray weeds. Only a minimum amount of chemical is applied this way, and only where it's needed.

Turflon

This chemical will kill oxalis and kikuyu grass in fescue, ryegrass and bluegrass lawns. These are stubborn weeds. Little can be done without the aid of Turflon. Spot spray infested areas, and follow up a week or two later and as needed. Turflon can be combined with Trimec to control a wide variety of weeds.

MSMA

MSMA kills crabgrass when it first sprouts, and it kills nutsedge. Crabgrass is a stubborn weed. If you have an infestation, you should use a pre-emergence herbicide in February in Southern California or March in Northern California. Spray if weeds show up in June and July. Nutsedge is stubborn too. It often begins in areas with poor drainage. Correct the drainage if possible. Repeat sprays of MSMA may be necessary to suppress this weed. MSMA can also be combined with Trimec to controll broadleaf weeds as well.

  Weeds in Groundcovers and Shrub Beds

Here again, we have two fronts on which to fight weeds with herbicides. We can deal with them before they sprout and after they sprout.

Ornamec

Ormanec will kill grassy weeds in flower and shrub beds. Look at the label to see which plants can be sprayed without damage. The same chemical is also found in Ortho's Grass-B-Gon, available in small hand held sprayers. It will kill Bermuda grass and annual weedy grasses growing up into shrubs and groundcovers such as ivy. There's no other way to get rid of a tangle of Bermuda grass that has managed to grow up inside of a Juniper. This is a welcome aid where it's needed.

Roundup

This herbicide kills almost any plant. Be careful with it. Apply it only to weeds you want to kill. Do not let it touch plants you do not want to harm, including lawns. It doesn't take much to do damage.

Treflan and Surflan

These are just two of the chemicals used in pre-emergence herbicides, weed preventers. There are several products on the market in both granular and liquid forms. Amaze and Preen seem to be widely available. These can be used in planting beds on bare ground to prevent weeds for six months or more. Apply in October and March, at the beginning and at the end of the rainy season. If there is no rain, you will need to water them into the ground for their actions to be effective. These chemicals kill weeds as they germinate. They do not prevent weeds that sprout from roots or bulbs. You'll have to dig those out.

© 1998 by Jim Clatfelter         Go to Garden California Home Page

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