Answer: In general, aromatic plants confuse pests by masking the scent of their host plants. Mints of any kind that are fragrant and suited to your area are fine, but since they are very invasive, should be grown in pots in your vegetable and flower beds. Other aromatic herbs such as garlic, onions, tansy (grow this in pots, too), marigolds, nasturtium, and larkspur. Many of these also attract beneficial insects seeking nectar, especially mints and plants in the carrot family that produce umbrella-shaped blooms (caraway, dill, Queen Ann's Lace). The cayenne I'm familiar with is a hot pepper, which, like other peppers, likes warm temperatures and well-drained, fertile soil, and is a tender annual plant that is killed by frost. The plant itself doesn't deter pests, but the peppers are hot and spicy, and can be pureed and diuted in water to make an insect and animal-repelling spray. Any hot pepper will do, and Burpee offers many options. Your local greenhouse may, too. I didn't find any references that salvia clevelandii is more aromatic or pest repellent than other sage plants, but if it smells strong, I don't see why you couldn't try it. For more information on companion planting, check out Carrots Love Tomatoes, by Louise Riotte and Companion Plants by Philbrick and Gregg.
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