Getting Rid of Weeds on Hardscape

This article authored by: Catherine Hallberg


Rancho del Lago Vail, AZMany of us rejoiced when we moved from homes with lawns to those featuring rock landscaping.

No more mowing or pulling weeds, or so we thought. Those nasty little critters find their way up through the rocks in dismaying abundance. What to do? Pre-emergent and post-emergent herbicides are widely employed to keep weeds at bay. Here’ s a few facts about these chemicals so that you can decide what will work best for you.

Pre-emergents prevent seed germination by inhibiting a key enzyme. Post-emergents kill weeds which are already established. The main thing to remember when using either is that timing is everything.

Pre-emergents should be applied twice a year:  in the fall (September-October) and in early spring (February-March). The key is to apply them before the weeds start to appear. A good rule of thumb is to notice when they sprung up this year and count backwards 3 weeks. That’s when to apply the pre-emergent. Most of these herbicides are applied in liquid or granular form.

The liquids used are typically dithiopyr, oryzalin, pendimethalin and prodiamine. Granules such as Amaze utilize benefin plus oryzalin and can be easier to apply and will fall through foliage so coverage can be better.

To be completely absorbed, watering is required afterwards or if you’re lucky enough to have ½” of rainfall, that will suffice. Otherwise the herbicide just lays on top of the rocks and you’ve wasted your money. Both the initial application and subsequent watering should be done during calm weather to avoid drift. Some children and pets are sensitive to these products and could experience adverse effects from blowing herbicide.

For this reason, some homeowners prefer to use natural products. Corn gluten meal (CGM) which is a remnant of corn syrup processing is the most prevalent. It works by drying out the soil surface so the germinated seed dries up and dies. If the soil never completely dries out from rain or irrigation, the CGM can actually become a fertilizer causing the weed to grow more. Not what you expected! Herbicidal “soaps” such as Scythe are effective on small annuals, but won’t kill large annuals and perenials.

The other method for weed treatment after they appear is using post-emergents. Care should be taken when using as some are selective and will kill only certain types of weeds and others will kill everything, including your plants and flowers. Read the label before buying.

Of course, there’s the tried and true method of pulling weeds by hand. Mulching can be a weed deterrent as well. Nothing will get rid of them 100% as the seeds can blow from neighbors’ yards or be carried in on shoes and pets. If you maintain constant treatment, you’ll definitely see a big difference.

Hope you find this information to be helpful. The good news is that you can sell your lawnmower!!Central Tucson Stucco Home

Rob and Catherine Hallberg are Associate Brokers with Long Realty, a Berkshire-Hathaway Affiliate and Southern Arizona’s largest Brokerage. Since 2008, they have been ranked in the top 5% to 8% of all U.S. REALTORS®. Send Rob and Catherine an email for a fast response to your questions; for an even faster response, Call (520) 407-8667


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