PEPPERMINT

Best kept in containers as this plant can overtake your whole garden. Keep it well watered.

A study in the Stress & Health journal found the peppermint aroma may be useful for relieving stress — even more so than lavender. The study found that cortisol (one of the hormones responsible for high stress levels) was significantly decreased after exposure to peppermint.

“Chew a few fresh leaves and you’ll be feeling fresh and ready to go,” says Campbell.