Does catnip (Nepeta cataria, pronounced NEP-eh-tuh kat-AR-ee-ah) repel mosquitos? A recent article in iScience says, “Yes.” (Read the full text here.)
A perenial herb, catnip is among a group of plants that produce compounds, called iridoids, which discourage insect attacks. Two of these compounds are nepetalactol and nepetalactone. The latter substance attracts cats, who often nibble the leaves or rub against the plants. A couple of our felines prefer to dive into the middle of mine as if they are wading pools on a steamy day. Then they aimlessly race around (“the zoomies”) for a while before they collapse for a nap. If disturbed, they may open their dilated eyes and acknowledge my presence with a little chirp, almost as if saying, “That’s some good Nip, man.”
Now, science tells us that those same compounds are an effective mosquito repellant. A research collaboration between Northwestern University and Lund University (published in Current Biology journal) indicate that crushed catnip can be as effective as the synthetic compound DEET and is safer. Silver vine (Actinidia polygama), a relative of the Kiwi vine, has even more insect-fighting substances although it is less commonly grown.
Simply growing catnip near your deck, pool, or treehouse will not do the deed. Leaves must be damaged (torn or bruised) to release the mosquito-fighting magic. The oil from crushed catnip leaves also repels fruit flies.
Catnip is easily started from seed or can be divided. It will grow in full sun to part sun in any well-drained soil, zones 3 through 9, preferring part sun in hotter zones. It has attractive spikes of blue-to-purple flowers that bees and butterflies love. As a member of the mint family, square-stemmed catnip is a vigorous grower and can become woody and shrub-like with age. Prune it back hard after blooming to encourage repeat flowering and keep the plant compact. The next time I prune those in the Mary Snoddy garden, I plan to put squashed leaves and stems around the deck to test out the mosquito-repelling scheme.
Nom, nom, nom.
