Make way for native plants | Garden Notes

Barbara Faurot
Posted 4/20/22

April is Native Plant Appreciation Month in Washington. It’s a time to enjoy the beauty of our native plants and celebrate the gifts they offer to pollinators and wildlife. 

Why, then, …

This item is available in full to subscribers.

Please log in to continue

E-mail
Password
Log in

Make way for native plants | Garden Notes

Posted

April is Native Plant Appreciation Month in Washington. It’s a time to enjoy the beauty of our native plants and celebrate the gifts they offer to pollinators and wildlife. 

Why, then, are we going to talk about weeds? 

One of the best ways to encourage native plants is to reclaim space for them to thrive. Weeds can rapidly invade our gardens, farms, and forests, competing for nutrients, water, and sunlight. They can also suppress beneficial mycorrhizal connections among plants. 

Our goal is to make room for native flora by discouraging weeds, using methods that support healthy habitat for plants and wildlife. 

Christine Heycke, WSU Jefferson County Master Gardener and recently appointed member of the county’s Noxious Weed Control Board, shared her research to “weed out the truth” on the variety of control methods used by home gardeners, from hand weeding to commercial herbicides to popular home remedies. 

“It’s best to use a science-based approach,” Christine explains. “Many home remedies may appear to work in the short term, but have unintended consequences for other plants and soil microbes.”

Home Remedies: Myth vs. Fact

Some home remedies can break down into salts or change the soil pH. Examples include epsom or other salts, bleach, baking soda, ammonia, or vinegar. These substances can kill soil organisms, slow plant growth, and find their way into groundwater. 

“Even if the effects on soil pH are temporary, you could end up killing some of your neighboring plants,” shares Christine. In short, it’s best not to put caustic chemicals on or near healthy soil, as they can damage nearby plants and soil biota. 

Other home remedies such as boiling water or weed torches are more benign and can work well in the short-term, especially if they are used on young plants without fully developed root systems. Boiling water will work on the top of a young plant, but the heat probably won’t penetrate the soil deeply enough to kill all parts of a mature weed. Weed torches are good for gravel paths and in between pavers, but may be ineffective on plants with strong root systems, bulbs, or tubers. Follow directions carefully and avoid using torches during dry weather or near anything combustible.

Hand weeding with your tool of choice is a tried and true way to discourage weeds. “Scraping” weeds off the surface of the soil, or cutting them as close to the ground as you can, is one way to effectively deprive them of nutrients. You may need to repeat the process for several cycles, but eventually most plants will exhaust their resources.

Herbicide Use and Risks

Commercial herbicides, whether selective or non-selective, can kill weeds, but can also result in over-spray or vapor drift, potentially damaging natives and other desirable plants. Research results vary on how long herbicides remain in the soil and how they affect flora and fauna. If gardeners do choose to use chemical controls such as glyphosate, it’s critical to follow all directions and precautions carefully. 

Feed Your Soil

Above all, keep in mind the essential job of soil microorganisms–breaking down organic matter and making nutrients available to plants. The most beneficial methods of weed control are those that not only deter weeds, but also support the health and well-being of these soil microbes.

The big winner in Christine’s research is mulch. “A coarse, organic mulch is a great way to keep weed seeds from sprouting. It also preserves soil moisture and temperature. It eventually breaks down, enriching the soil.” 

Good choices include arborist chips, dried and shredded leaves, crushed nut shells, coarse sifted compost, or conifer needles. Contrary to another common myth, mulching with fir or other conifer needles does not acidify the soil. Decomposing organisms will break down the needles, and they won’t affect soil pH.

Even better, celebrate Native Plant Appreciation Month by planting a living mulch to deter weeds and support pollinators and wildlife. Good native ground covers include Gaultheria precumbens (wintergreen), Mahonia repens (creeping Oregon grape), Arctostaphylos uva-ursi (kinnikinnick), Oxalis oregana (redwood sorrel), Vancouveria planipetala (inside-out flower), and Fragaria chiloensis (coastal strawberry). 

WSU’s fact sheets offer more research-based methods for specific weeds: hortsense.cahnrs.wsu.edu/Home/HortsenseHome.aspx.

The Master Gardener Plant Clinic team is resuming live Zoom sessions to address your gardening questions from noon to 2 p.m. Thursdays  starting May 5. Sign up at jefferson.wsu.edu/plant-clinic.

Save the Date

The 2022 Master Gardener Plant Sale will be in-person from 9 a.m. to 2 p.m. Saturday, May 7 in the Chimacum High School parking lot. The sale benefits the Jefferson County Master Gardener Foundation. 

Barbara Faurot is a Jefferson County Master Gardener and Master Pruner, working with other volunteers who serve as community educators in gardening and environmental stewardship. 

Comments

No comments on this item Please log in to comment by clicking here