|Common Name||Scientific Name||Helps||Helped by||Attracts||Repels||Avoid||Comments|
|Geraniums||Pelargoniumspp.||Roses, corn, peppers, grapes||leafhoppers, Japanese beetles||Tomatoes, Tobacco, Eggplants and other nightshades||A trap crop, attracting pests away from roses and grape vines, distracts beet leafhoppers, carrier of the curly top virus, keep away from Solanaceous plants like eggplant, and tobacco|
|Lupin||Lupinus||Cucurbits, brassica, lettuce, rosemary, dill, strawberry||summer savory||Honeybees||tomatoes and other solanaceae||This wildflower is a legume, hosting bacteria that fixes nitrogen in the soil, fertilizing it for neighboring plants|
|Marigold||Asteraceae Calendula Tagetes||most plants, especially tomatoes and peppers, cucurbits (cucumbers, gourds, squash), brassicas (broccoli, kale, cabbage)||snails||nematodes, beet leaf hoppers, other pests||Marigolds are a wonder-drug of the companion plant world, invoking the saying "plant them everywhere in your garden". French marigolds produce a pesticidal chemical from their roots, so strong it lasts years after they are gone. Mexican marigolds do the same, but are so strong they will inhibit the growth of some more tender herbs. Certain Varieties of marigolds (Tagetes) can help manage eelworms (Root-knot nematode) when planted the year before .
Tagetes has also been found effective against perennial weeds such as Ranunculus ficaria (Celandine), Aegopodium podagraria (Ground elder), Glechoma hederacea (Ground ivy), Agropyron repens (Couch grass), Convolvulus arvensis (Field bindweed), Equisetum arvense (Field/Common Horsetail) and other 'starchy' weeds.
|Petunia||Petunia x hybrida||cucurbits (squash, pumpkins, cucumbers), asparagus||leafhoppers, Japanese beetles, aphids, asparagus beetle||Is a trap crop almost identical to geraniums in function|
|Nasturtium||Tropaeolum majus||Many plants, especially cucurbits (melons, cucumbers, gourds), beans, tomatoes, apple trees, brassicas (broccoli, cabbage, etc.), radish||predatory insects||aphids, cabbage looper, squash bug, white fly, cucumber beetles||radish, cauliflower||Both work as trap crops for aphids, is among the best at attracting predatory insects|
|Sunflower||Helianthus annuus||corn, tomatoes||aphids||Was grown as a companion for corn(maize) before modern Europeans arrived in the Americas, supposedly increases their production, ants herd aphids onto sunflowers, keeping them off neighboring plants|
|Tansy||Tanacetum vulgare||cucurbits (cucumbers, squash, etc.), raspberries and relatives, roses, corn||sugar ants, Japanese beetles, cucumber beetles, squash bugs, mice||Toxic to many animals, don't plant it where livestock browse|
|Yarrow||Achillea millefolium||many plants||predatory wasps, ladybugs, hoverflies, damselbugs||May increase the essential oil production of some herbs. Also improves soil quality, use the leaves to enrich compost, or as mulch.|
|Zinnia||Zinnia||beans, tomatoes, peppers||whiteflies||Attracts hummingbirds that eat whitflies, attracts pollinators|