Control weeds with herbicides

Published 12:00 am Sunday, February 27, 2011

I had numerous calls and questions last week pertaining to the article on weed control with selected herbicides. I apologize if I created a little confusion over some of the products some of you are using. Therefore, today let me clear up some of the confusion I may have caused.

Q. Can I use 2, 4-D to treat my St. Augustine lawns?

A. For year round use I would recommend atrazine as a good active ingredient to use when treating St. Augustine lawn for both warm season and cool season weed control. Some of you were questioning whether or not 2,4-D was harmful to St. Augustine grass. The home lawn care products that contain 2,4-D as active ingredients use a much less concentrated amount of the ingredient when compared to 2,4-D products used in the production agriculture areas. Concentrated 2,4-D products can cause injury to home lawns containing St. Augustine.

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However, if your lawn care provider is using a home lawn herbicide or weed and feed combination containing 2,4-D it is likely at a low concentrations and designed to help provide better broadleaf control in St. Augustine lawns without injury to St. Augustine grass. I apologize for this confusion. When in doubt read the label and always follow its directions.

Please keep in mind I am reporting to you the labeled restrictions, not my opinion. For instance, many of the atrazine products may not recommend atrazine use on Bermuda lawns or fields. This is because research has indicated atrazine may have some activity primarily on our hybrid Bermuda grasses. With that being said, I have never seen this occur but it is on the label so I am giving you the facts. 2,4-D is safe at most levels on Bermuda and centipede lawns.

Q. Will my yard being dormant have any effect on what I spray?

A. The labels on herbicide products apply to lawns whether they are dormant or active. However when lawn are dormant they are less resistant to injury that may occur when actively growing in midsummer.

I have not seen any major damage to yards from being sprayed by an incorrect herbicide or weed killer lately. However, I have seen multiple yards and gardens over the last few years that were damaged because the homeowner used a product like Roundup and did not clean out the sprayer before mixing up the next product. This is why we recommend if you spray herbicides, insecticides, and fungicides around your home it is a safe investment to simply purchase another spray tank and avoid mixing herbicides with other sprays.

I have also seen damage from what we call drift. This happens when you have weeds growing all around the edge of your flower beds or vegetable garden and you decide to spray them on a slightly windy day. I see this several times every year. Droplets drift from the intended area onto desirable plants and then the damage is done.

For these reasons, I may recommend some of you to look at using some of the organic products when possible to reduce some of these problems. If you don’t feel comfortable or have the equipment we have numerous qualified landscape companies in the Miss-Lou that can assist you.