Winning against Weeds

Redroot pigweed seedlings appear after mid-summer rainstorms

While mid-summer thunderstorms bring a welcome relief from the heat, they also spur the growth of summer weeds. In July and August, weeds like spotted spurge, purslane, redroot pigweed and lamb’s quarters threaten to take over, often seemingly overnight.

Sometimes it’s satisfying to pull a few weeds. But spending the whole summer weeding can be a real drag. As you weed, it’s important to consider how you can prevent them in the future. It’s nice to do other things with your time besides weeding.

Here are some ideas to help you get control of weeds in the long term.

Where there is bare soil, there will be weeds.

Purslane has thick, succulent leaves and red stems.

In some dry climates, you can leave the soil bare because there’s simply not enough moisture for weeds to germinate very often. Colorado is not one of these climates. It may take a few months, but Colorado receives enough rain that weeds will eventually colonize any bare soil. It’s inevitable.

If you have areas of your yard that have exposed soil, think about how you’ll cover the soil once you remove the weeds. You can cover soil with pathways and patios, but you’ll probably need to cover some areas with mulch. Check out my “How to Mulch” guide if you need some help figuring out how to tackle a mulching project. Homeowners who have read it have told me they have found it very helpful.

Covering bare soil is one of the most effective things you can do to reduce the amount of weeding your landscape requires. In the landscapes I care for, I strive to have no bare soil showing at all.

Wood/bark mulches are very effective at suppressing weeds.

Spotted spurge grows close to the ground. It thrives on bare soil and in gravel mulch.

One of the wonderful qualities of mulches made from wood or bark products is that they are very good at keeping new weeds from germinating. The key here is that the mulch layer has to be thick enough. If it’s too thin, weed seeds will blow in the patches of bare soil and germinate. Also, the weeds seeds already in the soil will be able to get enough light to begin growing.

In order to maximize the weed-suppressing benefits of mulch, make sure the layer is three to four inches deep. Check out this post for more information about topdressing mulch.

Landscape fabric is not the answer.

Although “landscape fabric” or “weed barrier” seems like a good idea, it’s not truly a long-term solution for preventing weeds. It’s true you won’t get many weeds in the first few years after you install it, but after a while dust, dirt and weed seeds start collecting on the surface of the fabric under the mulch. Weeds will eventually grow on top of the fabric.

Rather than relying on landscape fabric as a way to prevent weeds, choose a different strategy.

In areas covered with rock mulch, you have to control weeds regularly.

Rock mulch can be a good option to cover the soil in certain conditions. It’s a much better choice than leaving the soil bare. Just be aware that you’ll have to be consistent about controlling weeds since they love to grow amongst rocks.

Lamb’s quarters seedlings have a blue-color and triangular leaves.

Here are a couple of options. The first option is to hand weed regularly– like weekly. The second option is to use a weed preventer chemical in spring and mid-summer. The third option is to spot spray weeds with a weed killer.

Frankly, I use a combination of all three methods to keep rock mulch free of weeds. Even if there was landscape fabric installed under the rock, it’s eventually necessary to adopt a regular weed control program.

Remove weeds before they produce seeds.

Most mid-summer weeds germinate from seeds each year. It follows then, if you’d like fewer weeds in the future you shouldn’t let this year’s weeds produce new seeds. That means you need to remove them before they flower and set seed. Try to pull them in the next couple of weeks. Don’t wait until late summer.

So after the Independence Day barbecues are over, break out the gloves and weeding tools. As you’re pulling them out, ponder what you can do to prevent new weeds in the future. Any long-term actions you take will be effort well spent!