Five plants that mosquitoes hate

NO one likes to have mosquitoes hanging around the house — not only are they irritating but some also carry viruses that are harmful to humans. There are some plants that repel insects, including mosquitoes, and although they may not have been proven effective, some people still have them around, hoping that they will help make their homes less friendly to bugs.

Shaan Lalwani, a young horticulturist and landscaping designer based in Mumbai, India, shares his top five favourite plants that can repel mosquitoes. These plants can be added to your garden, yard or balcony, although you may need a number of them to be effective. Their leaves can also be crushed and rubbed onto the skin to keep mosquitoes at bay. To avoid an allergic reaction, do try it on a small part of the skin first.

1. Peppermint/horsemint/spearmint

Oil from the peppermint plant has been evaluated for larvicidal activity against different species of mosquitoes such as Aedes aegypti and Anopheles. In fact, it was found that mosquitoes are not the only insects that hate the smell of peppermint. Ants, spiders, cockroaches, ticks, mice and even lice will be repelled too.

Planting tips: Well-drained soil; partial to full sunlight (three to four hours); 30 to 50ml of water for a six-inch pot, avoid waterlogging.

2. Rosemary

This plant has been used for centuries to keep pesky mosquitoes away. Researchers at Seoul National University in South Korea have found that rosemary volatiles repelled mosquitoes as well as or even better than diethyltoluamide (DEET), and that the volatiles lasted as long as DEET.

Planting tips: Well-drained red soil, add coco peat or small stones to make it more permeable; partial to full sunlight (two to three hours); 30 to 50ml of water for a six-inch pot, avoid waterlogging.

3. Carnivorous plants

Nepenthes or pitcher plants and venus flytraps “eat” mosquitoes and other small insects rather than repel them. Insects are drawn into the pitchers by their attractive scent and sometimes colourful pigmentation.

Planting tips: Poor nutrient-free soil; generally likes bright sunlight without much direct sun; 30 to 50ml of water for a six-inch pot, use distilled, rain or well water only.

4. Citrosa

This is a popular natural insect repellent. Its qualities have been verified by research, including its effectiveness against Aedes mosquitoes. The plant is actually a variety of the scented geranium that produces the citronella scent when the leaves are crushed.

Planting tips: Well-drained soil; full outdoor sunlight; 30 to 50ml of water for a six-inch pot, avoid waterlogging.

5. Catnip

We all know cats love catnip, but not mosquitoes. The oil from the leaves has been proven to be 10 times more effective than DEET in repelling mosquitoes. Apart from its intoxicating effect on cats and repelling mosquitoes, the leaves make a very soothing tea as well.

Planting tips: Light, well-drained soil; can be kept both indoors and outdoors; 30 to 80ml of water for a six-inch pot.

This article first appeared in property+, a section of the digitaledge DAILY, on Sept 18, 2015. Download property+ for free here.