Using Roundup On Patio Can Damage Nearby Trees

by Ms. Grow-It-All on April 28, 2011

in Weekly Column Archive

Q: Over the past few summers, I’ve used extended control Roundup in late spring to kill the weeds that come up between the pavers on my patio. Last fall, we planted a couple of small trees near the patio to provide shade, and my neighbor says they’ll die if I use the Roundup this year. I certainly don’t want to kill the trees. Is she right? What should I use?

A: There’s an ongoing debate about how long Roundup and its active ingredient, glyphosate, stay in the soil. Critics challenge the validity of company-sponsored research; supporters question the agenda of those with opposing views. The main thing to remember is this:

Roundup is a poison. It kills things. It is a non-selective, broad-spectrum herbicide, meaning it kills anything and everything in its path. Extended control is a stronger version of the original, so it’s more poisonous. With anything poisonous, you should use caution when applying.

Depending on how close your trees are to the patio, their root zones probably extend under the pavers. Anything you spray on the pavers can leach down through the soil. Plus, there’s always the possibility of spray drifting over to the trees and nearby plants, no matter how careful you are when applying the herbicide.

The safest, least toxic solution is to pull the weeds by hand, but a lot of people don’t find that idea appealing. Boiling water will kill the grass, as will white vinegar, and neither should harm your tree if you don’t overdo the application.

Another solution is to plant groundcover between the pavers. They’ll choke out the weeds and give a nice, soft look to the patio. Ask your local nursery staff or check out for perennials that can take foot traffic.

Garden Tours: Mark your calendars for a couple of upcoming garden tours that are sure to give you plenty of ideas for your own yard. The Tallahassee Area Rose Society is sponsoring an open house of local rose gardens this Sunday from 1 to 4 p.m., and the annual Tallahassee Tour of Gardens to benefit Maclay Gardens State Park is May 14. The Maclay tour is a little later than usual this year, because the colder-than-normal winter caused things to bloom later than usual. Details for both tours are available on the event calendar on my website,

Native wildflowers: If you’re considering adding native wildflowers to your garden, check out the Panhandle Native Wildflower Mini-Symposium on May 14 at the University of Florida Research and Education Center in Quincy. Yes, it’s the same day as the Maclay tour but the symposium ends at 12:30, so you might be able to do both. See my website for details.

Internet radio show: Ms. Grow-It-All on Blog Talk Radio airs at 5 p.m. today (Thursday) at This week’s conversation is about pets and the garden. If you can’t join us live, you can download a podcast of the program.


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