Editor’s note: This is the July installment of a monthly column written by the city of DeKalb’s Citizens Environmental Commission that focuses on increased awareness of issues such as promoting projects and ordinance changes involved in recycling, reducing energy consumption, and planting native habitat.
We are fortunate to live in the Midwest with some of the richest soil in the country.
If you have property in DeKalb established before the era of topsoil conservation, your yards are composed of that same rich soil that greeted the earliest settlers to Illinois. However, those settlers brought foreign plants or seeds with them either for aesthetic reasons or as tag-alongs in baggage.
Many of these have now become the ubiquitous “noxious weeds,” such as creeping thistle, mock strawberry and creeping Charlie. If you wish to establish lawn or create a section of native habitat, invasive non-natives may need to be eliminated first. Safe, effective removal without chemical herbicides is challenging.
If unwanted vegetation covers a space where you don’t want to grow anything else for at least six months, smother the area under layers of cardboard or sheets of black plastic.
As another option during the heat of summer, place thin clear plastic across the area and leave in place for four to six weeks. The sun heats the ground and kills weed roots and seeds but, unfortunately, the intense heat also kills beneficial organisms.
For spot removal, you can use a propane torch to scorch weeds, particularly in spaces hard to access such as cracks in pavement. Even boiling water is an effective spot application method!
There are natural weed control methods that combine vinegar, salt and dish soap. As it may be difficult to grow plants in the soil affected, however, it’s best for patios and pavement cracks.
With several applications, undiluted 5% white vinegar will kill small, young annual weeds down to the roots. For older weeds and tough perennials, you’ll need 20% strength horticultural vinegar. While residue from high concentration vinegar is safe around children and pets, it’s lethal to bees and can burn skin, harm eyes and cause bronchitis if inhaled. For future plantings, however, it degrades promptly in the soil.
One inexpensive product is borax (sodium borate), a fairly strong nonselective weed killer.
If you wish to buy a commercial product, a quick biodegradable solution is one made from D-Limonene (citrus oil). Its residues are safe around animals and the water supply, and it kills the plant down to its root.
Another natural commercial solution is ammoniated soap of fatty acids with maelic hydrazine, which poses minimal risk to animal and insect species. Products with this combination state you can sow seeds within 5 days of spraying. With this product and all others, the user should read all warning labels closely to determine if food crops or only non-edibles may be planted in the sprayed areas.
Avoid glyphosate, as it is not only harmful to the environment but also to the individual. It is reported to be a probable carcinogen by the World Health Organization and was found to significantly increase the risk of non-Hodgkin lymphoma (NHL), a cancer of the immune system.
After treatment and establishment of desired plants, weeds are bound to appear in the future, whether native or introduced. What should you do after your prized annuals and perennials are finally in place? It’s spot-spraying and hand-pulling time! Enjoy your garden!
Please visit the Citizens’ Environmental Commission at bit.ly/DklbCEC and the City of DeKalb Facebook page.
- Clare Kron is a member of the city of DeKalb’s Citizens Environmental Commission.