The citronella plant is a great fly repellent! Burning citronella candles will also do the trick, because flies not only hate the plant's scent but also tend to stay away from flames and smoke.

What smell will keep flies away?

Cinnamon – use cinnamon as an air freshner, as flies hate the smell! Lavender, eucalyptus, peppermint and lemongrass essential oils – Not only will spraying these oils around the house create a beautiful aroma, but they will also deter those pesky flies too.

Does citronella keep black flies away?

More commonly used to repel mosquitos, citronella oil may also be an effective and natural black fly repellent. ... Use citronella oil topically or in a candle for the best results in repelling black flies.