use of round up weed control in urban environment

Asked July 8, 2016, 5:26 PM EDT

We live in a large condominium between NW Naito Parkway and the Willamette River. Our property extends to the banks of the river. Our landscaper has been using a diluted version of Round Up to control weeds on the property and blackberry vines along the edge of the river. We have LOTS of dogs in our complex, and some of our residents like using the rosemary growing here for cooking. We have read that Round Up when diluted is safe for the environment, pets, birds and even run off to the river. Does the Master Gardner agree with this. Thank you.

Multnomah County Oregon

1 Response

Glyphosate is the active ingredient (a.i.) in Roundup and a number of other trade named products. It is widely used by homeowners (it is widely available in any hardware store or garden center), farmers, foresters, and invasive weed specialists for controlling plants. When it was first introduced in the mid-1970s, it was widely adopted because if its effectiveness in controlling some difficult to manage perennial weeds and because of its low acute toxicology in comparison to many of the other herbicides that were used at the time. It acts by moving through photosynthetic parts of the plant (leaves and some stems) down to the root system. Since it is bound up on soil, it doesn't enter plant roots in the soil.

There are some aquatic labeled forms of glyphosate that have been used to help manage some of the invasive plant species that we are getting in our riparian sites in the hope that these locations can be restored to native plant communities.

Here is a link that describes some of the general and toxicological characteristics of glyphosate: http://npic.orst.edu/factsheets/glyphogen.pdf . EPA reviews the efficacy and toxicological properties of any active ingredient (organic or conventional) before approving the product for use. The language on the label about how the product is to be used, safety issues with the product, disposal of the product, etc. is the result of their review of the a.i. and the risks that the product might have to the user, consumer, or anyone coming into inadvertent contact with the product. It is important to understand that in acute toxicology, the dose makes the poison. For example, a double espresso poses little risk but a teaspoon of pure caffeine can kill you. Risk is a combination of the degree of exposure to the a.i. and the inherent toxicology of the material. Assuming the applicator is using the product according to the label, there should be little risk in its use or your contact with it.

Some weeds can be very difficult/expensive to manage by hand pulling. The condo association I assume has some role is deciding how to manage weeds on the site and the budget for that management.

I hope this helps. If you have more questions, I would be happy to visit with you by phone. Chip

Chip Bubl OSU Extension Service Horticulture and Agriculture faculty,
Columbia County, OR 503 397-3462 chip.bubl@oregonstate.edu