Can borax be used to control creeping Charlie in the lawn?

Question:

Can borax be used to control creeping Charlie in the lawn?

Answer:

Borax has sometimes been touted to kill creeping Charlie (Glechoma hederacea) in lawns. Borax contains boron, an essential plant micronutrient. However, the difference between plant requirements and toxicity problems is very small. When excessive quantities are present, boron can damage and even destroy plants. We also know grasses tend to be more tolerant of excess boron than broad leaves. This potential "natural" weed management technique has much appeal to gardeners looking to avoid traditional herbicides, so applying a naturally occurring mineral like borax seems to be a better option.

Research done at Iowa State University in the early 1990s showed some promise for borax as a control for creeping Charlie.  After the two-year study, however, many questions were still not fully answered: How long does it remain in the soil? What effects, if any, will the boron have on nearby plants? How much borax is too much? These unanswered questions indicated a need for more research. A subsequent study done at the University of Wisconsin was conducted in much the same way and did not have the same results as the Iowa State study. Too many factors seem to influence how borax works in the soil, including soil pH and soil type.

This inconsistency in its effectiveness leads to much uncertainty about using borax as weed control.  Because the Iowa State study has not been replicated and so many factors influence its level of effectiveness, the use of borax as weed control for creeping Charlie is not recommended.

Persistent hand-pulling and/or broadleaf herbicides containing triclopyr and 2,4-D are the most effective control methods for creeping Charlie in the lawn. Learn more here: Control of Ground Ivy (Creeping Charlie) in Lawns and Gardens.