Did Pre-emergent Get On My Roses?

Q: I have a steep hill in my backyard with cotoneaster on the top and Drift roses at the bottom. The weeds in the cotoneaster are terrible so last year I used a pre-emergent. That didn’t help and I am concerned that the pre-emergent ran down into the roses because they didn’t perform too good this year. 

A: Pre-emergent chemicals are carefully designed to quickly cling to soil particles and to stay in place, despite the rainfall, while they prevent seeds from germinating and slowly decomposing. Your pre-emergent didn’t run down the hill so I very much doubt it harmed your roses. Your first job is to identify the weeds in your cotoneaster and then match the weed to the best method of control. Some weeds are impossible to control with chemicals in a shrub-covered area. Hand-pulling may be your only option. Take photos of the individual weeds, take them to your local plant nursery when it’s not busy, and ask employees to help.