All types of flies, including the common house fly and the stable fly, can ruin your ability to relax and enjoy your backyard landscape. Not only are these pests an ugly nuisance, but flies can also carry germs and diseases. You can make simple changes to your garden and modify your landscape to naturally repel flies.
Your compost pile is a source of rich food for your plants, but can also be the breeding ground for many kinds of flies. In fact, backyard compost heaps are one of the most common sources of fly problems outdoors. To repel flies and make your property less hospitable to these pests, follow all standard composting best practices. That includes not adding meat to the pile, and remembering to turn and mix the pile every two to three days. Regularly turn your compost pile to kill fly larvae and deter adult flies from making it their breeding spot. Additionally, chop up everything you add to the pile to a size of no larger than 2 inches in diameter. Bigger pieces attract flies, because there's more surface area for the flies to use for laying eggs.
Some say cleanliness is next to godliness. In your landscape, cleanliness is definitely next to fly-lessness. Keep your garden clean, and remove any rotting plants and overripe fruit immediately. Such plant matter attracts various kinds of flies, both because of the rotting smell and also because the decaying plant matter is often a food source for the flies. This includes overripe tomatoes and other vegetable crops, rotting flower bulbs and decomposing leaves that have fallen off of your trees. Not only does cleaning up your garden enhance its appearance, it also makes your landscape less favorable to flies.
Excessive moisture in your yard can attract many types of flies -- water can be a food source, creates the moist habitat needed for eggs and larvae to thrive, and speeds up the decaying of plant matter that some flies feed on. Clean out drains in outdoor sinks; remove leaves and built-up debris in rain gutters, and inspect any other sources of water in your backyard. Finally, water your plants only when necessary. Although some plants have specific needs, most plants should be allowed to dry out between waterings.
You have several options for trapping flies. Many garden stores sell inverted cone traps connected to a jug of bait liquid. The liquid's smell attracts flies, which enter the cone-shaped funnel and can't find their way out. Such traps only work if you've removed other sources of food, such as cleaning up your vegetable garden to remove fallen produce. Otherwise, the trap is competing with the other food sources for the flies' attention. If you have a localized fly problem, such as flies swarming around outdoor garbage cans, you can try sticky fly traps in the area.
Some herbs have pungent, sharp odors that naturally repel flies and may also cover up the smell of food in your landscape. However, to the human nose, these herbs can smell fragrant. To repel flies, grow basil (Ocimum basilicum) in areas where you notice fly activity. Or plant the basil in pots that you can move around to easily position where you need pest control. Basil thrives throughout U.S. Department of Agriculture plant hardiness zones 2 through 11. Alternatively, try growing lavender (Lavandula spp.), which flies also find repulsive. This herb grows in USDA zones 5 through 10.
Candles don't just add an ambient, romantic glow to your outdoor landscape. Repellent candles or torches infused with citronella oil also help drive away many kinds of flies. Citronella oil's citrus-like odor repels flies, and the smoke from candles and torches also helps cover up any other scents that could attract flies. In one research study, scientists found that citronella candles have an effective fly-repelling range of 2 to 3 meters. Exercise fire hazard caution when using candles in your backyard, keeping all candles out of the reach of children and pets and far away from anything flammable, such as grass, wood fencing, bark mulch and wood deck surfaces.