Garlic
Plant with: Roses, raspberries, cucumbers, peas, lettuce, and celery.
Get these benefits: The most popular allium for keeping aphids off roses, garlic repels Japanese beetles and spider mites, too.
Sweet Alyssum
Plant with: Potatoes, broccoli, beans, corn, and eggplant. Get these benefits: This sweet-smelling ground cover attracts predatory wasps and hoverflies, which devour aphids.
Borage
Plant with: Strawberries, cucumbers, squash, and tomatoes. Get these benefits: Ward off tomato worms. This annual also adds trace minerals to soil, helping boost disease resistance in nearby plants.
Mint
Plant with: Tomatoes and cabbage. Get these benefits: This quick-growing herb deters ants, fleas, aphids, cabbage moths, even rodents—plus it attracts earthworms, which help condition soil.
Alfalfa
Plant with: Lettuce, beans, and other legumes. Get these benefits: Add important minerals, such as nitrogen, iron, magnesium, phosphorous, and potassium, deep into your soil with this hardy perennial.
Scented Marigold
Plant with: Everything! Get these benefits: In dense clusters, this flower emits a substance that drives away harmful root-feeding nematodes. Near tomatoes, it can deter whiteflies.
Lavender
Plant with: Roses, alliums, and fruit trees.
Get these benefits: Discourage fleas and moths while drawing beneficial insects, such as bees, ladybugs, and praying mantises.
Nasturtium
Plant with: Cabbage, cucmbers, radishes, and fruit trees. Get these benefits: Repel squash bugs, whiteflies, and cucumber beetles. The blooms also keep aphids from nibbling on fruit trees.