broadleaf control on grass areas below trees

Asked June 27, 2019, 11:36 AM EDT

Plantain, creeping charley and dandelions are gradually overtaking my fescue grasses in the drip lines of large oak, maple, birch and evergreen trees. The various herbicides available to the general public have vague labeling or explicit warnings about using their spray products in these areas. What large area spray type weed killers are safe to use there and close to water bodies?

Dakota County Minnesota

3 Responses

The label is the law so if there is an explicit warning on a label it can’t be used in the prohibited application. Weed control is most effective in the fall when plants are taking in materials and concentrating them in their roots. It is also a better time to treat areas under trees when the chemicals in the spray are less volatile. Using a product as directed is important because using more than the prescribed amount can damage desirable plants like trees. Creeping Charlie is the hardest to kill of the 3 on your list. It will also take several seasons because there are also seeds in the ground. Feed Free Zone is effective on all three and can only be used 2 times in a year although it has been several years since I checked the label. So many products come on the market it is not possible to evaluate them all or keep up.

Could you identify the particular herbicides that are most damaging to tree's? With the ever changing trade names, using the chemical identity label on the product would help to screen out the harmful ones.

They are all damaging to some extent so the precautions of applying on a calm, cooler day and following application rates are important to protecting your trees. I could not find any lists about the relative risk from different products. Following directions and not over applying is most important. Products that have been on the market have been tested millions of times by purchasers and would not stay on the market if they killed trees. Obviously small, young trees are the most vulnerable.