The Easy-To-Grow Herb That Can Help Keep Pests Out Of Your Garden

Unwanted insects in your garden can be a nuisance for a number of reasons, including eating your hard-earned vegetables, or worse, biting you! But there is an easy-to-grow herb that you can plant to help keep pests out of the gardening space, and to prevent your legs from getting bitten up, too. According to entomological studies over the last decade and a half, rosemary (Salvia rosmarinus) is an effective repellent against a number of unwanted insect pests from thrips, to mosquitos, to ticks, and even spider mites. Hardy in USDA zones 8 to 10, rosemary's strong aroma wards off pests and discourages bugs from nesting on it, particularly those that are more attracted to sweet-smelling plants. Its noticeably warm, savory smell makes it unattractive to many critters (including deer), and therefore serves as an excellent barrier for other plants in your yard.

The same repellent properties in rosemary's scent translate into its oil as well, and you won't find bugs munching away at this plant for that reason. In fact, researchers believe that rosemary oil makes for a natural alternative to traditional bug sprays, illustrating just how strongly pests dislike the material. Furthermore, not only can you use rosemary oil on humans, extracting rosemary oil and applying it as a pesticide in your garden is also an effective tool against insect-intruders. Not only will the scent blanket your garden in a pungent aroma that bugs dislike, the oil itself effectively kills off soft-bodied pests without compromising the plants themselves. 

While rosemary is a general pest fighter in the garden, there are some specific plants, like vegetables that attract insects for nesting or eating, that benefit from rosemary as a companion. Brassicas, for instance, like broccoli, Brussels sprouts, cabbage, and kale, are susceptible to cabbage aphids, moths, and loopers, but rosemary's scent makes your brassicas far less attractive to them. Root vegetables are another garden crop that would benefit from rosemary's aromatic force field. Not only is the herb's scent too strong for bugs, like carrot flies, that feed on root veggies, but it actually masks the location of the vegetables, making it difficult for flies to land on them and lay eggs. Other veggies with insect enemies — beans and bean beetles, peppers with spider mites, strawberries with slugs to name a few — all see insect remediation when rosemary is planted nearby.

Given all of its benefits, it's fortunate for the pest-fighting gardener that rosemary can be quite easy to grow. While there are many different types of rosemary that may necessitate slightly different growing environments, for the most part, this herb does well in warmer, more Mediterranean-like climates. It can get up to five feet tall in some cases, but with regular trimming and pruning, you can easily maintain it to the perfect height you want. It's a good idea to replace your rosemary plants after five years. You can propagate new rosemary from cuttings, so your old plant is not a total loss. Plus, think of all the rosemary oil you can get from the old plant once you've removed it!