Asked November 7, 2020, 3:54 PM EST

Live in SW Portland, wooded and shaded area, many weeds in early spring. Should I use a pre emergent herbicide now or wait until Spring or should I use a post emergent herbicide in the spring thanks

Multnomah County Oregon

1 Response

Thank you for your question. Unfortunately, weed control is not a "one size fits all"
problem. Some plants that do not produce seeds cannot be controlled by preemergent herbicides, which only keep the seeds from germinating. These include plants with rhizomes, which spread under the soil, and are far more difficult to control. The use of post-emergent herbicides is often mis-used, and plants that were not targets are also inadvertently killed. So, first you have to identify what you have, and then proceed to finding an effective control mechanism. You might find the resources of the National Pesticide Information Center helpful: http://www.npic.orst.edu/

I hope this is helpful.