Master Gardeners In the Garden
Effective strategies for dealing with weeds
By Dana Cook
WSU Chelan/Douglas County Master Gardener
Despite its friendly-looking flowers, field bindweed is an invasive weed that can be tough to eradicate due to its root system reaching up to ten feet or more in depth. Teodor Buhl/Pixabay 
Dana Cook – WSU Master Gardener. – Provided photo/WSU Master Gardeners Perennial weeds can be a stubborn challenge for gardeners. These weeds come back year after year, seemingly with more resilience, turning our peaceful gardening hobby into all-out war. This past winter’s lack of snowfall and warmer temps reinforced the army of perennial weeds such as field bindweed (wild morning glory) and horsetail.
Knowing what you are up against can better prepare you for the battle. Perennial weeds spread by seed and persist by large root systems. They store energy in their underground structures, allowing them to regenerate even after being cut back or pulled. This is why effective weed control requires a combination of strategies and diligence!
Prevention
As with any health problem, prevention is the best method. Here are several methods:
- Mulching: Applying a thick layer of organic mulch in your planting beds can suppress weeds by blocking light. Mulch also improves soil structure, which helps your desirable plants outcompete weeds.
- Planting ground covers: Bare soil is a welcome mat for weeds. Ground cover plants, such as clover or creeping thyme, form a dense mat that can crowd out weeds.
- Proper soil preparation: Ensure your soil is fertile and well-draining to support your desirable plants. Consider no-till gardening to minimize soil disturbance, which brings weed seeds to the surface.
Physical Removal and Suppression
Once weeds are established, mechanical control is necessary.
- Hand weeding: Some may consider this labor intensive, although hand weeding can be a meditative garden activity. Whenever I have a life problem that needs sorting, I grab my weeding tool and get to work. Hand weeding is most effective if done early in the season when weeds are small.
- Solarization: Something to consider for next summer, solarization involves covering the soil with clear plastic for 4-8 weeks during the hottest part of the summer. This process heats the soil to a temperature that kills many weed seeds and roots.
- Mowing or cutting back: Regularly cutting back weeds prevents them from flowering and setting seed.
Chemical Control
If you are losing the weed war, it may be time to consider using herbicides. Use a selective herbicide that is targeted for the weed you are battling. Non-selective herbicides will kill all vegetation and need to be applied directly to the leaves of the weed. Most importantly, follow the instructions listed on the package.
Some resources to help you make herbicide decisions are Pesticide Information Center Online (PICOL) at https://picol.cahnrs.wsu.edu/, and Hortsense, a WSU platform that contains fact sheets to he10lp home gardeners with many plant problems. Find it at https://hortsense.cahnrs.wsu.edu/.
Finally, take advantage of the WSU Master Gardeners plant clinic, which is available year-round. You can email questions to askamastergardener@chelandouglasmg.org.
Long-term Management
Patience and persistence are your most effective weapons in the weed war. Regular monitoring with a combination of prevention, physical and chemical methods provide the best results.
Also, keep in mind that some plants considered “weeds,” such as dandelions and clover, are beneficial to your garden by being a food source for pollinators or having deep taproots that help break up compacted soil. Certain weeds, in moderation, can coexist in a balanced ecosystem without causing significant harm.
A WSU Chelan and Douglas County Master Gardener column appears weekly in The Wenatchee World. To learn more, visit bit.ly/MGchelandouglas or call 509-667-6540.
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