When planting our gardens, we select plants that are pleasing to us, fit well into our design and color scheme, paying attention to texture, seasonal interest and perhaps wildlife habitats. More and more we are also looking for a little help in repelling insects, rather than using manufactured insect repellents or pesticides. There are a number of plants that are happy to oblige, some of which probably have already taken up space in your garden. Below is a list of some of the more common natural insect repellents.
Plants in the mint family contain oils with aromatic properties that are repulsive to insects. This family is known to repel mosquitoes, flies, ants, mice and cockroaches. Keep in mind that the mint family is an aggressive grower, so container gardening is often a smart choice. Peppermint, basil and catnip all work well. In fact, catnip contains nepetalactone oil that is reported to be 10 times more effective in repelling mosquitoes than DEET.
Additional culinary herbs that help with repelling insects are: lemon thyme (mosquitoes), sage (flies, cabbage moths, and black flea beetles), rosemary (fleas, mosquitoes), lavender (spiders, ants and moths), chives (ants, aphids and flea beetles) and bay leaf (roaches). Dill is known to repel aphids, spider mites and squash bugs, but do not plant it near tomatoes as it can attract tomato hornworms. Dill also attracts ladybugs, an extremely beneficial insect, and swallowtail butterflies. Garlic is known to repel slugs, snails, ticks, some grubs, Japanese beetles and mosquitoes.
Flowers, such as marigolds contain pyrethrum, which is used in many insect repellents and their roots contain a chemical compound thiopenes, which repel aphids, cabbage maggots, white and black flies. They are particularly effective in repelling hornworms that prey on tomato plants. Ageratum secretes coumarin, a compound that is found extensively in manufactured mosquito repellents. Eucalyptus is another insect repellent as is beebalm, wormwood and lemon verbena.
The citronella plant, a member of the geranium family, is helpful with mosquitoes, cabbage worms and Japanese beetles. Citronella grass works the same way. Chrysanthemums also contain pyrethrum. This plant works well against roaches, fleas, ticks, bedbugs, lice, silverfish and ants. Petunias deter tomato hornworms, asparagus beetles, leaf hoppers, Mexican bean beetles and aphids. A tea made with petunias leaves can be a potent insect repellent.
All the above herbs, flowers and plants can help repel insects in your garden, but my favorite is lemon balm. I have had lemon balm growing in my herb garden for years. It is a little aggressive, so some containment is required. I have found nothing as effective in controlling insects. If I am out gardening and it is a particularly buggy day, I grab some leaves and rub them on my arms, legs and neck and carry on virtually insect free and the scent is very pleasing.
Keep in mind that it is the oils in the leaves of these plants that repel insects, so it helps if the leaves are shaken or crushed to get maximum protection. You can gather some leaves, crush them and place them in a decorative bowl on your patio table. Or you might want to make your own repellent by adding crushed leaves, especially from the herbs, to vodka, which is a proven mosquito repellent and letting it sit for about 12 hours. Once infused take your mixture and pour it into a spray bottle and use as you would any repellent. I have never tried this homemade mixture before, but I mean to this year and might even bring it to picnics in a pretty little spray bottle as a hostess gift. Happy gardening!
Marilyn Fanning | Greenhouse Design and Sales