CERTIFIED TEXAS EXPERT GARDENER — Winter weed management important for SETX lawn care

Published 12:16 am Wednesday, November 1, 2023

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Gardeners, we have now weathered our first “real” cool snap of the season, if but for only a few days with evening temperatures becoming downright cold in my opinion.

So, go ahead and roll your eyes, cause ‘everyone’ who knows this gardener, knows I’m partial to warm weather, though an infrequent ‘cooling off’ period is a welcome respite considering our blistering summer.

Hopefully, you relocated ‘sensitive’ plants indoors or provided them protection, as winter will arrive soon. A slight smattering of rainfall graced some portions of SETX, and though I’m grateful, the amount received was insignificant for most of us.

Perhaps more rain will soon be on the horizon?

Last week I stated weed control is sometimes complicated, which is certainly true if a gardener waits too long to begin a management strategy.

The review covered weed control measures utilizing numerous methods and further detailed how to control weeds utilizing pre- and post-emergent herbicides and herbicide classifications: such as contact, systemic, selective, or non-selective herbicides and specific weeds that each type of herbicide eradicates.

Before using any herbicide (synthetic or organic), we must understand the products intended use: weed type or group, application requirements (temperature sensitive), dose rate (application rate) and application frequency.

It is important that each of us follow the herbicide manufacturers label guidelines before applying herbicides to protect our environment!

Last week we discussed weed identification- a critical step in developing a weed control plan of action.

Create a weed management plan, then select the best herbicide option, to combat weeds such as broadleaves, grasses, perennial or annual weeds. Preemergent herbicide active ingredients are also an important factor for halting unwanted weeds and products always list a range of plants they control.

Preemergent herbicides are effective on annual weeds, though other weeds need to be controlled using post-emergent applications. Effective weed control and management begins with choosing the right active ingredient for the problem weeds, then applying it correctly.

My recommendation is always to use granular herbicides (if possible), simply due to ease of application. Read and follow product label details thoroughly and follow distance applications from desirable plants, which will avoid injuring them.

Wintertime weed management and having a ‘plan’ for what you can do now to keep lawn weeds from becoming unmanageable, weed infested areas before spring arrives.

As soil temperature cools, the application of preemergent herbicides to eradicate cool season weeds, such as annual bluegrass or burweed is now. According to AgriLife Extension turfgrass specialist, Chrissie Segars, Ph.D., who states, “applying the correct preemergence herbicides now to lawns will disrupt the germination and emergence of unfavorable plants in the spring. Applying preemergent herbicides in the fall will help to rid your lawn of grassy weeds like annual bluegrass, rescue grass, broadleaf weeds like henbit, chickweed, Carolina geranium and lawn burweed (sticker plants).”

She also recommends fall preemergent herbicide regimens, beginning when soil temperatures reach 70 degrees. As environmental conditions can be drastically different year to year, some weeds will germinate later in the season but applying products in a timely manner creates a preemergent “program,” which stays ahead of weeds.

For best results, one application of a preemergent herbicide in the spring and fall, as these two applications will greatly reduce the number of annual weeds in your yard.

Herbicides are not 100 percent effective, especially after heavy rains follow the application or when application timing is missed. Utilizing a mixture of pre- and post-emergent products will catch “breakthrough” weeds from the original application while they are immature.

Activating the herbicide after application by providing water using a sprinkler or irrigation system is highly recommended.

Most granular preemergent products require ¼ to ½ -inch of water to dissolve properly. Don’t wait for rain, this can be risky!

‘All in One’ Products

In case you missed my previous comments regarding “Weed & Feed” products, while they tend to be popular among gardening enthusiasts, homeowners, and some gardeners use them (not me). I do NOT recommend using them as a fall or winter turfgrass management tool!

We are entering a dormancy period for warm-season grasses, and their growth is slowing. It is too late in the season to fertilize our lawns, especially with nitrogen fertilizer.

Adding a nitrogen-based fertilizer now promotes growth, and winters freezing temperatures will cause substantial turfgrass damage. The final nitrogen fertilizer application should be no later than six to eight weeks before the average first frost date, which for our area is typically mid-December but could occur as early as mid-November.

Approximately 1 inch of water per week is the summertime turfgrass irrigation recommendation for actively growing grass. Once fall temperatures arrive (now), fall rain should be enough.

Allowing grass to visibly wilt before application of supplemental water is a good rule of thumb. If we are receiving typical fall rain, you can turn the sprinkler system off or water as needed until the grass goes dormant.

Don’t overwater, but moisture in the soil is necessary until grass goes dormant, protecting it from winterkill.

Spring preemergent herbicide applications typically start when soil temperatures reach 50-60 degrees, for us it is typically somewhere between January to March. Identify the weeds you have and note their location and create a “plan of attack” for getting your warm season turfgrasses off to a good start in spring.

So long for now fellow gardeners. Let’s go out and grow ourselves a greener, more sustainable world, one plant at a time!

Thank you for sending me your questions and please continue sending comments and questions to jongreene57@gmail.com.