Like most insects, mosquitoes thrive in warm wet conditions. Female mosquitoes lay their eggs in and around water, so periods of heavy rainfall can bring clouds of them into the garden – just when we are looking forward to enjoying the outdoors.
There’s no easy answer. Citronella candles only work in enclosed spaces. Bug zappers kill mostly beneficial insects, as mozzies are not attracted to the blue light. And keeping the garden looking good over the long hot Australian summers requires watering, which of course attracts mosquitoes.
There are a few things we can do in the garden, to help keep these bloodsuckers away.
Most of all, do not offer breeding grounds for mosquitos:
- Avoid stagnant water sources: empty watering cans before storing, check the saucers of all your outdoor pots, empty and clean bird baths and pet water bowls daily
- Prune shrubs and trees to allow good air flow, to avoid moisture accumulating on the foliage
- Water your garden in the morning, to avoid water droplets sitting on your plants overnight
- If you have puddles collecting in parts of your garden, or if you have a rain garden with standing water, sprinkle Bacillus thuringiensis over the water surface once a week. Bacillus thuringiensis is a naturally occurring biological insecticide that attacks mozzie larvae. It is not harmful to wildlife and pets drinking from treated puddles
Invite mosquito-eating predators into the garden. If you have a pond, most ornamental fish consume mosquito larvae. Lizards, geckos, dragonflies, frogs, and spiders dine on adult mosquitoes. Many smaller birds also eat them, including honey eaters.
Strong-smelling plants may also deter mosquitoes. In the spirit of ‘every little bit helps’, you could plant lavender, various kinds of mint, herbs like rosemary, basil, lemon verbena, or thyme in areas where you like to sit.
Because mosquitoes are not strong fliers, keeping your alfresco fan(s) on at full speed may create enough air disturbance to tumble them away before they can land on you. And of course, long sleeve shirts and long pants always help.
And if you would like to tackle the problem head on, a product like Richgro Indoor Outdoor Surface Spray kills and repels mosquitoes by forming a barrier around the home. Apply as a residual treatment to surfaces where insects rest or harbour such as window sills, door jambs, and fly screens. Reapply as necessary.
Birgit Daller is a horticulturist and garden designer, and the owner and creative head of Art of Green Landscapes & Design.