Every spring, garden centers stock "mosquito plants." They smell wonderful and grow easily, but a pot of citronella on the patio won't keep you from getting bitten.
Why living plants don't do much
The oils that repel insects are stored inside the leaves. A growing plant releases very little of them into the air. Crushing leaves releases more, and some concentrated plant oils do work as repellents, but a plant sitting in a pot has only a small effect beyond arm's length.
The plant often sold as "citronella plant" is actually a scented geranium, not the grass that citronella oil comes from, and studies have found it does little to deter mosquitoes.
Plants still worth growing
Aromatic plants such as lemongrass, lavender, catmint, rosemary, basil and bee balm are still great patio choices. They attract pollinators, several are edible, and brushing past them releases their scent. Catmint's oil in particular has shown repellent activity in lab studies.
What actually works
- Dump standing water. Mosquitoes can go from egg to adult in about a week in something as small as a bottle cap of water. Empty saucers, buckets, toys and clogged gutters weekly.
- Refresh birdbaths at least once a week, or use mosquito dunks made with Bti, a bacterium that targets mosquito larvae.
- Run a fan. Mosquitoes are weak fliers, and a steady breeze on a patio keeps many away.
- Use an EPA-registered repellent such as DEET, picaridin or oil of lemon eucalyptus when you're outside at dawn and dusk.
The "Mosquito-repelling" collection in the plant explorer lists aromatic plants for your area. Enjoy them for their scent and flowers, and pair them with the steps above.