By Barbara Brown
When we think of mint it is usually in the context of a flavoring agent for food and drinks. But can it also be an insect repellent? The answer is a qualified, “yes.” According to Texas A&M University, “Some herbs, such as mint, are unattractive to fire ants.”
“Unattractive” does not necessarily mean that mint acts as an ant repellent, but it does suggest that there is some basis for Grandma’s beliefs.
Cornell University conducted a research project using six essential oils, including peppermint, and found that “the Argentine ant (Linepithema humile) and the red imported fire ant crossed barriers treated with multiple rates of peppermint and other essential oils less frequently than paired control barriers. (Wiltz et al. 2007) After 24 hours of exposure to peppermint oil, Argentine ant mortality was almost 90%. The results were confirmed in a study that found 1% peppermint oil to be an effective repellent of Argentine ants for a period of one week. (Scocco et al. 2012).”
Although the fragrance of mint leaves is significantly less than that of mint essential oil, the leaves release a minty scent when touched or chewed. Informal reports from some gardeners confirm that they believe that their mint plants, specifically peppermint and spearmint, seemed to reduce the presence and damage from ant colonies in their gardens.
However, before you plant mint in your vegetable garden to keep away ants, you need to know that MINT SPREADS and it spreads aggressively through its underground root system. It is a garden bully! Left unbounded by a pot, it can quickly take over an area. It spreads so effectively that it can even be used as ground cover in open landscape areas. Growing mint in a container helps control the spread, but sneaky mint roots have been known to escape through the pot drainage hole and invade the surrounding area.
The Central Texas Gardener tells us “If you have the right conditions, mint’s the easiest plant to grow in the world. Mint plants are normally listed as needing full sun to perform well, but I found that here in scorching-hot Texas, my mint does much better with about half a day of shade.”
Several varieties of mint are offered in the spring at garden centers. These include, but are limited to:
- Peppermint (Mentha × piperita)
- Spearmint (Mentha spicata)
- Chocolate mint (Mentha × piperita f. citrata‘Chocolate’)
- Apple mint (Mentha suaveolens)
- Pennyroyal: (Mentha pulegiu)
Mint plants prefer well-drained soil with lots of organic material. The plants require supplemental water during the summer months and often die back. However, they return with vigor as soon as the weather cools in the fall. Surrounding the mint plants with mulch provides some heat protection and extends the spring-to-summer growing season. The plants disappear in the winter but return as soon as the soil begins to warm. To keep the plants bushy, frequent cutting during the growing season is recommended.
If you do not want to grow mint but would like to try its fragrance as an ant deterrent, try dampening cotton balls with mint essential oil and placing them strategically in your garden. Or, mix 20 drops of mint essential oil with water in a spray bottle and squirt where the ants are emerging in your soil. This needs to be repeated frequently.
Happy Gardening!
