There's so much more to a great yard than just mowing the lawn.

Late Summer Weed Control

With all the rain that fell in July in southern Colorado, the weeds have been growing, well, like weeds. It’s incredible to see them grow so quickly in warm, wet weather conditions.

Tall weeds will often eventually create tumbleweeds if neglected.

Tall weeds will often eventually create tumbleweeds if neglected.

If you haven’t gotten a chance to take care of them yet, it’s time to take action soon. Many of their seeds are just about to mature. If you don’t do anything, you will have millions of additional weed seeds disperse over your property. Think you have a problem now? Just wait until next year. And the year after that…and the year after that…

So, how do you control weeds in late summer? Here are some ideas:

Hand pull

I know pulling weeds is not that much fun on Labor Day weekend, but it’s the best way to remove weeds from an area. If you’re able to do it before the seeds drop from the plant, you take care of both this year’s problem and prevent future weeds. It’s also the best way to make an area look well-cared-for and tidier.

Hand pull short weeds in rock mulch and those growing in desirable landscape plants.

Hand pull short weeds in rock mulch and those growing in desirable landscape plants.

Hand pulling is also the best way to deal with short weeds that grow sideways like purlane, spotted spurge and redstem filaree. These weeds are too short to mow or string trim. It’s also a practical approach for rock mulch or gravel areas.

In addition, hand pulling is wise along fence lines where it’s hard to use a mower or string trimmer without damaging the fence. Hand pulling is really the only option when weeds are growing amongst desirable landscape plants.

For the best success, you need to pull out a good portion of the root. Grab the plant by the base and pull. If the soil is moist from your sprinklers or rain, it’s much easier for them to come out. I like to put them directly in a trash bag as I pull them out so if they have already gone to seed, at least some fall in the bag rather than on the ground.

Put the weeds in the trash or recycle them as yard waste through a landscape supply yard. Don’t put them in your own compost pile, especially if you’re not that consistent about building, watering and turning your pile regularly.


landscape weeds in late August

Mow or string trim taller landscape weeds before the seeds disperse.

If the weed is an annual plant (meaning it germinates, grows, flowers and dies all in one growing season), mowing will take care of the problem. Furthermore, if you’re dealing with weeds taller than 4 inches, mowing can be pretty effective. You won’t kill the plant by mowing, but you’ll chop up the flowers and future seeds so it won’t spread. As a bonus, when cold weather sets in the existing plant will die.

How do you know if you have an annual weed? If you didn’t notice the problem in previous summers and it just took over after the rains, it’s likely it grew from a seed this summer and it’s an annual plant.

Foothills vegetation in late August

Native grass, flowers and shrubs don’t have to be mowed in late summer.

It’s not necessary to mow natural areas with native grass, flowers and shrubs. These are not weeds, just stands of native vegetation.

Mowing works best in relatively flat areas without a lot of rocks or debris. Mowing will also take care of weeds that eventually break off at the ground and create tumbleweeds, like kochia and Russian thistle. These can be tough to pull out of the ground if the soil is dry. So, if you’ve got a weed forest on your hands, try mowing it.

String Trim

mowed weeds

Mowed weeds don’t create long-term problems for adjacent areas.

If you have tall weeds growing on a slope, in a narrow area, or in an area with lots of rocks or debris, string trimming is a good option.

I like to use a string trimmer in any area where I wish I could mow, but mowing doesn’t seem to be safe or practical. It essentially provides the same benefits as mowing, except that you get more flexibility because you can vary the height of the trimmer.

Can’t I spray the weeds with a weed killer?

You can, but it’s likely the weeds will produce seeds before the spray will kill them. By spraying late in summer, you take care of this year’s problem. However, this method doesn’t do anything to mitigate problems in future years.

At this time of year, it’s more effective to hand pull, mow or string trim and save your spray for earlier in the summer.

So, before you head out for the end-of-season camping trip, take a few minutes and make a dent in your weedy areas. You’ll be rewarded by a tidier landscape and less labor on Labor Day weekends in future years.

One Response to Late Summer Weed Control

  1. Carol September 22, 2017 at 2:19 pm #

    I’m new to north CO and appreciate any info I can get to make my lawn look better

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