Companion Planting

While I was at the Master Gardener's Expo, several people asked about companion planting.  As promised, I am posting some information on that subject.  This is by no means a complete list, but it should be extensive enough to get you going.

Companion Planting Guide
Basil	•          May repel flies, asparagus beetle, mosquitoes & thrips •          Beneficial with tomatoes, squash, strawberries, grapes & peppers •          Avoid planting with rue or sage
Bee Balm	•          Beneficial with tomatoes •          Attracts beneficial insects & bees
Catnip	•          May repel flea beetles, Japanese beetles, aphids, ants, weevils & squash bugs •          May repel rodents
Chamomile	•          Beneficial with cucumbers & onions •          Increases essential oil in peppermint •          Attracts hover flies & wasps
Chervil	•          Beneficial with broccoli, lettuce & radishes •          May repel aphids, slugs •          Incompatible with beans & peas
Chive	•          May repel tomato pests, aphids •          Beneficial with carrots, grapes, roses & tomatoes •          Helps prevent apple scab
Cilantro	•          Attracts beneficial insects
Clover	•          Nitrogen fixer •          Attracts beneficial insects, particularly predators of the wooly aphid
Dandelion	•          Emits ethylene gas that is beneficial to fruit trees
Dill	•          Attracts beneficial insects •          Incompatible with carrots, caraway & tomatoes •          Beneficial with cabbage, lettuce & onions •          May repel aphids, squash bugs •          Can attract the tomato horn worm
Eucalyptus	•          May repel ants, cabbage looper, & Colorado potato beetle
Fennel	•          May repel aphids (I have not found this to be so) •          Attracts beneficial insects •          Incompatible with dill, potatoes
Lavender	•          May repel fleas, moths & whitefly
Lemon Balm	•          May repel many bugs
Lovage	•          Beneficial with most plants •          Attracts ground beetles
Marjoram	•          Beneficial with vegetables & herbs
Mints	•          Attracts beneficial insects, particularly predatory wasps & hover flies •          Use cuttings to mulch beets •          May repel rodents, ants, cabbage moth, aphids, fleas, flea beetles •          Beneficial with cabbage & tomatoes
Oregano	•          Beneficial with grapes, cabbage, squash & hot peppers •          May repel cucumber beetles & cabbage butterflies
Parsley	•          Beneficial with tomatoes, roses, asparagus, carrot, hot peppers, chive & onion •          Attracts beneficial insects, particularly hover flies & parasitic wasps •          May repel asparagus beetles •          Incompatible with mints
Rosemary	•          Beneficial with hot peppers, carrots, beans, cabbage & sage •          May repel carrot flies, cabbage moths & bean beetles
Sage	•          May repel white cabbage butterflies, beetles, flea beetles, carrot flies & cabbage moths •          Incompatible with cucumbers •          Beneficial with cabbage, carrots, broccoli, cauliflower & rosemary
Tarragon	•          Beneficial with most vegetables •          May repel a variety of pests
Thyme	•          Beneficial with eggplant, potatoes & tomatoes •          May repel cabbage worms, whitefly & cabbage looper