The concept of companion planting goes back centuries. In nature, diverse ecosystems of plants live together, supporting and benefiting each other. You hardly ever see an entire field of one plant in nature.
Companion planting is the practice of planting certain non-crop plants next to your garden for a number of benefits:
- Attract beneficial insects
- Attract pollinators
- Repel pests
- Fixing nutrients back into the soil
- Providing ground cover or support
While it may seem counter-intuitive to the beginner gardener, we actually want to attract certain insects into our garden. In addition to pollination, beneficial insects such as lady bugs and praying mantises because they eat the pest insects like aphids.
Some companion plants do an especially good job of attracting pollinators with their brightly colored and fragrant flowers. We plant these around our vegetables with the notion that pollinators are lazy, and while they’re already there for the cosmos, they’ll stay around and pollinate our squash.
Other companion plants emit a strong odor that pests detest. Garlic, for example, repels slugs and aphids – which is great if we plant them next to our veggies who have a known weakness for aphids.
Plants such as beans, for example, fix nutrients back into the soil, making them available for neighboring plants. Other plants may absorb nutrients, but make it readily available when they are composted or tilled back into the soil. For more, check out my post on cover crops.
Plants that can be used as ground covering provide a lot of added benefits. Using them as a mulch provides the soil coverage, helping it retain water and prevent runoff during a storm. They also provide shelter and protection for some beneficial insects such as beetles and spiders.
I’ve collected a long list of common companion plants below. I’ve listed their common name, followed by the scientific name, and what they’re used for. I hope you find it helpful!
Very attractive to pollinators. Plant a row of agastache away from your crops to lure cabbage moths away. It is also a powerful medicinal herb.
Attracts beneficial insects such as predatory wasps, lacewings, ladybugs, syrphid fly. Can also be grown in place of using mulch for weed suppression. As a mulch, it provides shelter for ground beetles and spiders.
Plant as a mulch to shade the soil and retain water. Also protects ground beetles and spiders.
(Ammi majus; Ammi visnaga)
Attracts beneficial insects such as predatory wasps, lacewings, ladybugs, syrphid fly. Used as a general pest control plant.
Attracts beneficial insects such as honeybees, predatory wasps, lacewings and ladybugs.
Improves health and flavor of tomatoes and lettuce. Repels aphids, asparagus beetles, mites, flies, mosquitoes, and tomato horn worm.
Repels Colorado potato beetles.
Attracts beneficial pollinators such as bees, flies, and hummingbirds. Blooms in late summer.
Also attracts pollinators as well as beneficial predatory insects such as hover flies, pirate bugs, tachinid flies, and ladybird beetles.
Puts calcium back into the soil. Is a great cover crop to plow back into the soil. Buckwheat absorbs nutrients not available to other plants and makes it available when it’s composted back into the soil.
Attracts beneficial insects and pollinators. It also adds trace minerals back into the soil. Borage deters tomato hornworm, cabbage moth caterpillars, and deer. Excellent as a cover crop and composted back into the soil.
Repels a number of unwanted soil nematodes and asparagus beetles.
Attracts pollinators, cats and parasitic wasps. Catnip repels aphids, asparagus beetles, Colorado potato beetles, squash bugs and flea beetles.
Attracts hoverflies and parasitic wasps. It can also improve the flavor of onions.
Repels slugs and attracts parasitic wasps.
Improves the flavor of carrots and tomatoes. It repels aphids, carrot rust flies, Japanese beetles, and while flies.
Repels Japanese beetles. Attracts tachinid flies and parasitic wasps.
Repels aphids, potato beetles and spider mites. Attracts beneficial insects.
Fixes nitrogen back into the soil. Used for ground cover and mulch. Great composted back into the soil. Attracts beneficial insects like wooly aphids and ground beetles.
Adds nitrogen, potassium and calcium when composted back into the soil. Use as mulch. Predatory pest habitat.
Attracts beneficial insects such as pollinators, hoverflies, soldier bugs, and tachinid flies.
Provides food and habitat to parasitic wasps, tachinid flies, lacewings, hoverflies, pirate bugs, spiders, ladybird beetles, damsel bugs and other predatory insects.
Deters mice and voles from strangling trees. Plant in a tight circle (bulb to bulb) about 12” from tree trunks.
Attracts pollinators. Brings nutrients to the surface from deep down.
Improves overall health of cabbages and other Brassicas. Attracts beneficial insects such as ladybird beetles, parasitoid wasps, hoverflies, bees, garden spiders.
Attracts beneficial insects such as hoverflies and parasitic wasps. Helps to bring up nutrients from deep down to the surface.
(Foeniculum vulgare var. dulce)
Attracts beneficial insects such as ladybugs, syrphid flies, tachninid flies, parasitic wasps, and hoverflies. Strong repellent for aphids and fleas.
Blooms all season attracting pollinators.
Repels aphids, carrot rust flies, Japanese beetles, root maggots, spider mites, weevils, whiteflies, and more. Can be made into a tea or spray for a pesticide.
Acts as a mulch and ground cover to control weeds. Helps to build up soil and control erosion. Attracts beneficial insects.
Repels potato bugs.
Dynamic Accumulator extremely rich in silica; making tea for foliar spray; Promotes strong and healthy cell growth in fruit; considered anti-fungal; Can be invasive;
Bitter aroma confuses pest insects. It also deters cabbage moths.
Attracts beneficial insects such as hoverflies and ground beetles and pollinators
Acts as aphid trap
Repels snails and slugs.
Repels carrot rust flies.
Attracts parasitic wasps and ground beetles.
Fixes nitrogen into soil and attracts several species of lepidoptera.
Repels bad insects such as Mexican bean beetles, root knot nematodes, root lesion nematodes, whitefly, and cabbage worms. It also helps suppress other plant diseases.
(Cucurbita melo & Citrullus lanatus)
Leaves are full of calcium. Compost back into the soil.
Attracts earthworms, hoverflies and predatory wasps. It repels cabbage moths, aphids, flea beetles. It’s a great, easy ground cover that can improve other plants’ overall health.
Repels insects such as aphids, whiteflies, cucumber beetles, squash beetles, Colorado potato beetles, Mexican bean beetles, and root pests. Provides good ground cover for beetles and spiders. Attracts pollinators.
Repels carrot rust flies.
(Origanum vulgare/Origanum majorana)
Repels cabbage moths.
Repels Japanese Beetles
Attracts beneficial insects such as hoverflies and predatory wasps. Dried parsley leaves can be sprinkled on asparagus to repel asparagus beetles and sprinkled around roses to improve their scent.
Repels Mexican bean beetles.
(Raphanus raphanistrum subsp. sativus)
Deters most squash and cucumber pests. Pulls flea beetles from other veggies.
Repels cabbage moths, Mexican bean beetles, carrot rust flies, snails, and slugs.
Attracts beneficial insects such as hoverflies and parasitic wasps.
Will deter maggots and Japanese beetles.
Repels cabbage moths, carrot rust flies, fleas, beetles, and slugs.
Attracts beneficial insects such a hoverflies and tachinid flies.
Increases disease resistance of neighboring plants and repels insects.
Attracts honeybees and repels cabbage moths. Improves the flavor of beans and onions.
Attracts pollinators such as bees and ladybugs, particularly those best for squash and pumpkins. Improves the flavor of corn.
Provides food for flies and a habitat for predatory insects.
Repels a number of insects such as ants, flea beetles, flying insects, codling moths, Japanese beetles, squash bugs and striped cucumber beetles. The strong aroma confuses pest insects.
Deters most types of pests.
All-around beneficial plant for the garden. It repels insects such as cabbage moths, cabbage worms and snails and slugs. Also improves the flavor of nearby strawberries.
Attracts beneficial insects such as parasitic wasps, flies, solider bugs.
Repels flea beetles.
Attracts earthworms and hover flies. It fixes phosphorus back into the soil.
Attracts beneficial insects such as hoverflies, lady beetles, and wasps. It also repels aphids. Added to the compost bin, it helps speed up decomp. It’s rich in copper, nitrogen and phosophorus.