Companion Crop(s) Planting
A short guide to possible complementing plants
Many plants have natural substances in their roots, flowers, leaves etc. that can alternately repel (anti-feedents) and/or attract insects depending on your needs. In some situations they can also help enhance the growth rate and flavor of other varieties. Experience shows us that using companion planting throughout the landscape is an important part of integrated pest management. In essence companion planting helps bring a balanced eco-system to your landscape, allowing nature to do its’ job. Nature integrates a diversity of plants, animals, and other organisms into every ecosystem so there is no waste. The death of one organism can create food for another, meaning symbiotic relationships all around.
By using companion planting, many gardeners find that they can discourage harmful pests without losing the beneficial allies. There are many varieties of herbs, flowers, etc. that can be used for companion plants. Be open to experimenting and find what works for you. Some possibilities would be using certain plants as a border, backdrop or interplanting in your flower or vegetable beds where you have specific needs. Use plants that are native to your area so the insects you want to attract already know what to look for! Plants with open cup shaped flowers are the most popular with beneficial insects.
Companion planting can combine beauty and purpose to give you an enjoyable, healthy environment. Have fun, let your imagination soar. There are many ways you can find to incorporate these useful plants in your garden, orchard, flower beds etc.
Following is a basic plant guide (with some tips) to help you “work in harmony with nature.”
Note: this guide is not intended to solve garden problems as the suggestions may work differently in various situations or not at all. Don’t let that discourage you from giving the ideas a try! What works for some may not work for others and vice versa. Experimenting is the only way we can gain new insight for our own individual gardens.
ALFALFA: Perennial that roots deeply. Fixes the soil with nitrogen, accumulates iron, magnesium, phosphorous and potassium. Withstands droughts with it’s long taproot and can improve just about any soil! Alfalfa has the ability to break up hard clay soil and can even send its’ roots through rocks! Now that is a tenacious plant! Alfalfa is practically pest and disease free. It needs only natural rainfall to survive.
AMARANTH: A tropical annual that needs hot conditions to flourish. Good with sweet corn, it’s leaves provide shade giving the corm a rich, moist root run. Host to predatory ground beetles. Eat the young leaves in salads.
ANISE: Licorice flavored herb, good host for predatory wasps which prey on aphids and it is also said to repel aphids. Deters pests from brassicas by camouflaging their odor. Improves the vigor of any plants growing near it. Used in ointments to protect against bug stings and bites. Good to plant with coriander.
ARTEMISIAS: See Wormwood
BASIL: Plant with tomatoes to improve growth and flavor. Basil can be helpful in repelling thrips. It is said to repel flies and mosquitoes. Do not plant near rue.
BAY LEAF: A fresh leaf bay leaf in each storage container of beans or grains will deter weevils and moths. Sprinkle dried leaves with other deterrent herbs in garden as natural insecticide dust. A good combo: Bay leaves, cayenne pepper, tansy and peppermint.
For ladybug invasions try spreading bay leaves around in your house anywhere they are getting in and they should leave.
BEANS: All bean enrich the soil with nitrogen fixed form the air. In general they are good company for carrots, brassicas, beets, and cucumbers. Great for heavy nitrogen users like corn and grain plants. French Haricot beans, sweet corn and melons are a good combo. Keep beans away from the alliums.
BEE BALM ( Oswego, Monarda): Plant with tomatoes to improve growth and flavor. Great for attracting beneficials and bees of course. Pretty perennial that tends to get powdery mildew.
BEET: Good for adding minerals to the soil. The leaves are composed of 25% magnesium making them a valuable addition to the compost pile if you don’t care to eat them. Companions are lettuce, kohlrabi, onions and brassicas. They are also beneficial to beans with the exception of runner beans.
BORAGE: Companion plant for tomatoes, squash, strawberries and most plants. Deters tomato hornworms and cabbage worms. One of the best bee and wasp attracting plants. Adds trace minerals to the soil and a good addition the compost pile. The leaves contain vitamin C and are rich in calcium, potassium and mineral salts. Borage may benefit any plant it is growing next to via increasing resistance to pests and disease. It also makes a nice mulch for most plants. Borage and strawberries help each other and strawberry farmers always set a few plants in their beds to enhance the fruits flavor and yield. Plant near tomatoes to improve growth and disease resistance. After you have planned this annual once it will self seed. Borage flowers are edible.
BRASSICA: Benefit from chamomile, peppermint, dill, sage, and rosemary. They need rich soil with plenty of lime to flourish.
BUCKWHEAT: Accumulates calcium and can be grown as an excellent cover crop. Attracts hoverflies in droves. (Member of the brassica family.)
CARAWAY: Good for loosening compacted soil with it’s deep roots so it’s also compatible next to shallow rooted crops. Tricky to establish. The flowers attract a number of beneficial insects especially the tiny parasitic wasps. Keep it away from dill and fennel.
CATNIP: Deters flea beetles, aphids, Japanese beetles, squash bugs, ants and weevils. We have found it repels mice quite well: mice were wreaking havoc in our outbuildings, we spread sprigs of mint throughout and the mice split! Use sprigs of mint anywhere in the house you want deter mice and ants. Smells good and very safe.
CHAMOMILE, GERMAN: Annual. Improves flavor of cabbages, cucumbers and onions. Host to hoverflies and wasps. Accumulates calcium, potassium and sulfur, later returning them to the soil. Increases oil production from herbs. Leave some flowers unpicked and German chamomile will reseed itself. Roman chamomile is a low growing perennial that will tolerate almost any soil conditions. Both like full sun. Growing chamomile of any type is considered a tonic for anything you grow in the garden.
CHERVIL: Companion to radishes for improved growth and flavor. Keeps aphids off lettuce. Said to deter slugs. Likes shade.
CHIVES: Improves growth and flavor of carrots and tomatoes. Keeps aphids help to keep aphids away from tomatoes, mums and sunflowers. Chives may drive away Japanese beetles and carrot rust fly. Planted among apple trees it helps prevent scab and among roses it prevents black spot. You will need patience as it takes about 3 years for plantings of chives to prevent the 2 diseases. A tea of chives may be used on cucumbers and gooseberries to prevent downy and powdery mildews. See chive tea on disease page.
CHRYSANTHEMUMS: C. coccineum kills root nematodes. (the bad ones) It’s flowers along with those of C. cineraruaefolium have been used as botanical pesticides for centuries. (i.e. pyrethrum) White flowering chrysanthemums repel Japanese beetles. To the right is a picture of the painted daisy from which pyrethrum is extracted.
CLOVER: Long used as a green manure and plant companion. Attracts many beneficials. Useful planted around apple trees to attract predators of the woolly aphid.
COMFREY: Accumulates calcium, phosphorous and potassium. Likes wet spots to grow in. Traditional medicinal plant. Good trap crop for slugs. More on comfrey.
CORIANDER: Repels aphids, spider mites and potato beetle. A tea from this can be used as a spray for spider mites. A partner for anise.
COSTMARY: This 2-3 foot tall perennial of the chrysanthemum family helps to repel moths.
CUCUMBERS: Cucumbers are great to plant with corn and beans. The three plants like the same conditions warmth, rich soil and plenty of moisture. Let the cucumbers grow up and over your corn plants. A great duet is to plant cukes with sunflowers. The sunflowers provide a strong support for the vines. Cukes also do well with peas, beets and carrots. Dill planted with cucumbers by attracting beneficial predators.
DAHLIAS: These beautiful, tuberous annuals that can have up to dinner plate size flowers repels nematodes!
DILL: Improves growth and health of cabbage. Do not plant near carrots or caraway. Best friend for lettuce. Attracts hoverflies and predatory wasps. Repels aphids and spider mites to some degree. Also may repel the dreaded squash bug! (scatter some good size dill leaves on plants that are suspect to squash bugs, like squash plants, yeah that’s the ticket.) Dill goes well with onions, cabbage, sweet corn and cucumbers. Dill does attract the tomato horn worm so it would be useful to plant it somewhere away from your tomato plants to keep the destructive horn worm away from them. We like to plant it for the swallowtail butterfly caterpillars to feed on. Even their caterpillars are beautiful.
ELDERBERRY: A spray (see insect treatments) made from the leaves can be used against aphids, carrot root fly, cuke beetles and peach tree borers. Put branches and leaves in mole runs to banish them. Yes, it works!
FLAX: Plant with carrots, and potatoes. Flax contains tannin and linseed oils which may offend the Colorado potato bug. Flax is an annual from 1-4 feet tall with blue or white flowers that readily self sows.
FOUR-O’CLOCKS: Draw Japanese beetles like a magnet which then dine on the foliage. The foliage is pure poison to them and they won’t live to have dessert! It is important to mention that Four O’clock are also poisonous to humans. Please be careful where you plant them if you have children. They are a beautiful annual plant growing from 2-3 feet high with a bushy growth form.
GARLIC: Plant near roses to repel aphids. Accumulates sulfur: a naturally occurring fungicide which will help in the garden with disease prevention. Garlic is systemic in action as it is taken up the plants through their pores and when used as a soil drench is also taken up by the roots. Has value in offending codling moths, Japanese beetles, root maggots, snails, and carrot root fly. Researchers have observed that time-released garlic capsules planted at the bases of fruit trees actually kept deer away! Hey, worth a try! Concentrated garlic sprays have been observed to repel and kill whiteflies, aphids and fungus gnats among others with as little as a 6-8% concentration! It is safe for use on orchids too.
Try concentrated Garlic Barrier Insect Repellent!
Geranium: -Repels cabbage worms and Japanese beetles, plant around grapes, roses, corn, and cabbage.
GOPHER PURGE: Deters gophers, and moles.
GRAPES: Hyssop is beneficial to grapes as are beans, peas, or blackberries. Keep radishes and cabbage away from grapes. Planting clover increases the soil fertility for grapes. Chives with grapes help repel aphids. Plant your vines under Elm or Mulberry trees!
HORSERADISH: Plant in containers in the potato patch to keep away Colorado potato bugs. There are some very effective insect sprays that can be made with the root. Use the bottomless pot method to keep horseradish contained. Also repels Blister beetles. We have observed that the root can yield anti-fungal properties when a tea is made from it. (See: Horseradish: Disease)
HOREHOUND: (Marrubium Vulgare) like many varieties in the mint family, the many tiny flowers attract Braconid and Icheumonid wasps, and Tachnid and Syrid flies. The larval forms of these insects parasitize or otherwise consume many other insects pests. It grows where many others fail to thrive and can survive harsh winters. Blooms over a long season, attracting beneficial insects almost as long as you are likely to need them. For best results use horehound directly as a companion plant. Stimulates and aids fruiting in tomatoes and peppers.
HYSSOP: Companion plant to cabbage and grapes, deters cabbage moths and flea beetles. Do not plant near radishes. Hyssop may be the number one preference among bees and some beekeepers rub the hive with it to encourage the bees to keep to their home. It is not as invasive as other members of the mint family making it safer for interplanting.
KELP: When used in a powder mixture or tea as a spray, this versatile sea herb will not only repel insects but feed the vegetables. In particular we have observed that kelp foliar sprays keep aphids and Japanese beetles away when used as a spray every 8 days before and during infestation times. If you have access to seaweed, use it as a mulch to keep slugs away.
LAMIUM: This will repel potato bugs- a big problem for many gardeners!
LARKSPUR: An annual member of the Delphinium family, larkspur will attract Japanese beetles. They dine and die! Larkspur is poisonous to humans too!
LAVENDER: Repels fleas and moths. Prolific flowering lavender nourishes many nectar feeding and beneficial insects. Use dried sprigs of lavender to repel moths. Start plants in winter from cuttings, setting out in spring.
LEEKS: Use leeks near carrots, celery and onions which will improve their growth. Leeks also repel carrot flies.
LEMON BALM: Sprinkle throughout the garden in an herbal powder mixture to deter many bugs. Lemon balm has citronella compounds that make this work: crush and rub the leaves on your skin to keep mosquitoes away! Use to ward off squash bugs!
LOVAGE: Improves flavor and health of most plants. Good habitat for ground beetles. A large plant, use one planted as a backdrop. Similar to celery in flavor.
MARIGOLDS: (Calendula): Given a lot of credit as a pest deterrent. Keeps soil free of bad nematodes; supposed to discourage many insects. Plant freely throughout the garden. The marigolds you choose must be a scented variety for them to work. One down side is that marigolds do attract spider mites and slugs.
French Marigold (T. patula) has roots that exude a substance which spreads in their immediate vicinity killing nematodes. For nematode control you want to plant dense areas of them. There have been some studies done that proved this nematode killing effect lasted for several years after the plants were These marigolds also help to deter whiteflies when planted around tomatoes and can be used in greenhouses for the same purpose. Whiteflies hate the smell of marigolds.
Mexican marigold (T. minuta) is the most powerful of the insect repelling marigolds and may also overwhelm weed roots such as bind weed! It is said to repel the Mexican bean beetle and wild bunnies! Be careful it can have an herbicidal effect on some plants like beans and cabbage.
MARJORAM: As a companion plant it improves the flavor of vegetables and herbs. Sweet marjoram is the most commonly grown type.
MELONS: Companions: Corn, pumpkin, radish and squash. Other suggested helpers for melons are as follows: Marigold deters beetles, nasturtium deters bugs and beetles. Oregano provides general pest protection.
MINT: Deters white cabbage moths, ants, rodents, flea beetles, fleas, aphids and improves the health of cabbage and tomatoes. Use cuttings as a mulch around members of the brassica family. It attracts hoverflies and predatory wasps. Earthworms are quite attracted to mint plantings. Be careful where you plant it as mint is an incredibly invasive perennial. We have found that placing mint (fresh or dried) where mice are a problem is very effective in driving them off!
MOLE PLANTS: (castor bean plant) Deter moles and mice if planted here and there throughout the garden. Drop a seed of this in mole runs to drive them away. This is a poisonous plant. See Moles: Critter Trouble
MORNING GLORIES: They attract hoverflies. Plus if you want a fast growing annual vine to cover something up morning glory is an excellent choice.
NASTURTIUMS: Plant as a barrier around tomatoes, radishes, cabbage, cucumbers, and under fruit trees. Deters wooly aphids, whiteflies, squash bug, cucumber beetles and other pests of the cucurbit family. Great trap crop for aphids (in particular the black aphids) which it does attract, especially the yellow flowering varieties. Likes poor soil with low moisture and no fertilizer. It has been the practice of some fruit growers that planting nasturtiums every year in the root zone of fruit trees allow the trees to take up the pungent odor of the plants and repel bugs. It has no taste effect on the fruit. A nice variety to grow is Alaska which has attractive green and white variegated leaves. The leaves, flowers and seeds are all edible and wonderful in salads!
Try our recipe for: Nasturtium Salad
NETTLES, STINGING: The flowers attract bees. Sprays made from these are rich in silica and calcium. Invigorating for plants and improves their disease resistance. Leaving the mixture to rot, it then makes an excellent liquid feed. Comfrey improves the liquid feed even more. Hairs on the nettles’ leaves contain formic acid which “stings” you.
ONIONS: Planting chamomile with onions improves their flavor. Other companions are savory, carrot, leek, beets, kohlrabi, strawberries, brassicas, dill, lettuce and tomatoes. Intercropping onions and leeks with your carrots confuses the carrot and onion flies! Onions planted with strawberries help the berries fight disease. Keep onions away from summer savory and peas.
OPAL BASIL: An annual herb that is pretty, tasty and said to repel hornworms!
OREGANO: Can be used with most crops but especially good for cabbage. Plant near broccoli, cabbage and cauliflower to repel cabbage butterfly and near cucumbers to repel cucumber beetle. Also benefits grapes.
PARSLEY: Plant among and sprinkle the leaves on tomatoes, and asparagus. Use as a tea to ward off asparagus beetles. Attracts hoverflies. Let some go to seed to attract the tiny parasitic wasps and hoverflies. Parsley increases the fragrance of roses when planted around their base. Rose problems? See: Rose Rx for answers.
PEAS: Peas fix nitrogen in the soil. Plant next to corn and they will provide extra nitrogen. Corn is a heavy feeder so this is a great combination! Companions for peas are bush beans, Pole Beans, Carrots, Celery, Chicory, Corn Cucumber, Eggplant, Parsley, Early Potato, Radish, Spinach, Strawberry, Sweet pepper and Turnips. Do not plant peas with onions.
PEPPERMINT: Repels white cabbage moths, aphids and flea beetles. It is the menthol content in mints that acts as an insect repellant. Bees and other good guys love it.
PEPPERS, BELL (Sweet Peppers): Plant peppers near tomatoes, parsley, basil, and carrots. Onions make an excellent companion plant for peppers. They do quite well with okra as it shelters them and protects the brittle stems from wind. Don’t plant them near fennel or kohlrabi. They should also not be grown near apricot trees because a fungus that the pepper is prone to can cause a lot of harm to the apricot tree. Peppers can double as ornamentals, so tuck some into flowerbeds and borders. Harvesting tip: The traditional bell pepper, for example, is harvested green, even though most varieties will mature red, orange, or yellow. Peppers can be harvested at any stage of growth, but their flavor doesn’t fully develop until maturity.
PEPPERS, HOT: Chili peppers have root exudates that prevent root rot and other Fusarium diseases. Plant anywhere you have these problems. Teas made from hot peppers can be useful as insect sprays. Hot peppers like to be grouped with cucumbers, eggplant, escarole, tomato, okra, Swiss chard and squash. Herbs to plant near them include: basils, oregano, parsley and rosemary
PENNYROYAL: Repels fleas. Many people are now using pennyroyal as an alternative lawn. The leaves when crushed and rubbed onto your skin will repel chiggers, flies, gnats, mosquitoes and ticks. Smells nice too!
PETUNIAS: They repel the asparagus beetle, leafhoppers, certain aphids, tomato worms, Mexican bean beetles and general garden pests. A good companion to tomatoes, but plant everywhere. The leaves can be used in a tea to make a potent bug spray.
POACHED EGG PLANT: Grow poached egg plant with tomatoes, they will attract hover flies and hover flies eat aphids.
POTATO: Companions for potatoes are bush bean, members of the cabbage family, carrot, celery, corn, dead nettle, flax, horseradish, marigold, peas, petunia, onion and Tagetes marigold. Protect them from scab by putting comfrey leaves in with your potato sets at planting time. Don’t plant these around potatoes: cucumber, kohlrabi, parsnip, pumpkin, rutabaga, squash family, sunflower, turnip and fennel. Keep potatoes and tomatoes apart as they both can get early and late blight contaminating each other.
PURSLANE: This edible weed makes good ground cover in the corn patch. Use the stems, leaves and seeds in stir-frys. Pickle the green seed pod for caper substitutes. If purslane is growing in your garden it means you have healthy, fertile soil!
RADISH: Companions for radishes are: radish beet, bush beans, pole beans, carrots, chervil, cucumber, lettuce, melons, nasturtium, parsnip, peas, spinach and members of the squash family. Why plant radishes with your squash plants? Radishes may protect them from squash borers! Anything that will help keep them away is worth a try. Planting them around corn and letting them go to seed will also help fight corn borers. Chinese Daikon and Snow Belle are favorites of flea beetles. Plant these at 6 to 12 inch intervals among cole crops. In one trial, this measurably reduced damage to broccoli. Keep radishes away from hyssop plants. Planting an early row of radishes may lure flea beetles away from susceptible plants. For some good eating radishes try our delicious Purple Plum Radishes
ROSEMARY: Companion plant to cabbage, beans, carrots and sage. Deters cabbage moths, bean beetles, and carrot flies. Use cuttings to place by the crowns of carrots for carrot flies. Zones 6 and colder can overwinter rosemary as houseplants or take cuttings.
RUE: Deters aphids, fish moths, flea beetle, onion maggot, slugs, snails, flies and Japanese beetles in roses and raspberries. Companions for rue are roses, fruits (in particular figs), raspberries and lavender. To make it even more effective with Japanese beetles: crush a few leaves to release the smell. Has helped repel cats for us. You should not plant rue near cucumbers, cabbage, basil or sage. A pretty perennial with bluish-gray leaves. May be grown indoors in a sunny window. Rue may cause skin irritation in some individuals. Remedy: See cats and dogs: Rue spray.
RYE: An excellent use of plant allelopathy is the use of mow-killed grain rye as a mulch. The allelochemicals that leach from the rye residue prevent weed germination but do not harm transplanted tomatoes, broccoli, or many other vegetables.
SAGE: Use as a companion plant with broccoli, cauliflower, rosemary, cabbage, and carrots to deter cabbage moths, beetles, black flea beetles and carrot flies. Do not plant near cucumbers, onions or rue. Sage repels cabbage moths and black flea beetles. Allowing sage to flower will also attract many beneficial insects and the flowers are pretty. There are some very striking varieties of sage with variegated foliage that can be used for their ornamental as well as practical qualities. More on sage.
SOUTHERNWOOD: Plant with cabbage, and here and there in the garden. Wonderful lemony scent when crushed or brushed in passing. Roots easily from cuttings. Does not like fertilizer! It is a perennial that can get quite bushy. We have started to cut it back every spring and it comes back in not time. A delightful plant that is virtually pest free.
SOYBEANS: They add nitrogen to the soil making them a good companion to corn. They repel chinch bugs and Japanese beetles. Soybeans are so good for you! They are many ways to prepare them.
SQUASH: Companions: Corn, melon and pumpkin. Helpers: Borage deters worms, improves growth and flavor. Marigolds deters beetle. Nasturtium deters squash bugs and beetles. Oregano provides general pest protection
SUMMER SAVORY: Plant with beans and onions to improve growth and flavor. Discourages cabbage moths, Mexican bean beetles and black aphids. Honey bees love it.
SUNFLOWERS: Planting sunflowers with corn is said by some to increase the yield. Aphids a problem? Definitely plant a few sunflowers here and there in the garden. Step back and watch the ants herd the aphids onto them! We have been doing this for years and it is remarkable. The sunflowers are so tough that the aphids cause very little damage and we have nice seed heads for our birds to enjoy! Talk about a symbiotic relationship!
TANSY: Plant with fruit trees, roses and raspberries keeping in mind that it can be invasive and is not the most attractive of plants. Tansy which is often recommended as an ant repellant may only work on sugar type ants. These are the ones that you see on peonies and marching into the kitchen. At least for us placing tansy clippings by the greenhouse door has kept them out. Deters flying insects, Japanese beetles, striped cucumber beetles, squash bugs, ants and mice! Tie up and hang a bunch of tansy leaves indoors as a fly repellent. Use clippings as a mulch as needed. Don’t be afraid to cut the plant up as tansy will bounce back from any abuse heaped on it! It is also a helpful addition to the compost pile with its’ high potassium content.
Tansy Warning: You do not want to plant Tansy anywhere that livestock can feed on it as it is toxic to many animals. Do not let it go to seed either as it may germinate in livestock fields.
TARRAGON: Plant throughout the garden, not many pests like this one. Recommended to enhance growth and flavor of vegetables.
THYME: Deters cabbage worms. Wooly thyme makes a wonderful groundcover. You may want to use the upright form of thyme in the garden rather than the groundcover types. Thyme is easy to grow from seeds or cuttings. Older woody plants should be divided in spring.
TOMATOES: Tomato allies are: asparagus, basil, bean, members of the cabbage family, carrots, celery, chive, cucumber, garlic, head lettuce, marigold, mint, nasturtium, onion, parsley, pepper, marigold, pot marigold and sow thistle. Basil repels flies and mosquitoes, improves growth and flavor. Bee balm, chives and mint improve health and flavor. Borage deters tomato worm, improves growth and flavor. Dill, until mature, improves growth and health, mature dill retards tomato growth. Enemies: corn and tomato are attacked by the same worm. Kohlrabi stunts tomato growth. Keep potatoes and tomatoes apart as they both can get early and late blight contaminating each other.
WHITE GERANIUMS: These members of the pelargonum family draw Japanese beetles to feast on the foliage which in turn kills them.
WORMWOOD: Keeps animals out of the garden when planted as a border. An excellent deterrent to most insects. A tea made from wormwood will repel cabbage moths, slugs, snails, black flea beetles and fleas effectively. The two best varieties for making insect spray are Silver King and Powis Castle. Adversely Powis castle attracts ladybugs which in turn breed directly on the plant. Silver Mound is great as a border plant and the most toxic wormwood. Note: As wormwood actually produces a botanical poison do not use it directly on food crops.
See More on wormwood. for more details.
For insect spray: See wormwood spray
YARROW: Yarrow has insect repelling qualities and is an excellent natural fertilizer. A handful of yarrow leaves added to the compost pile really speeds things up. Try it! It also attracts predatory wasps and ladybugs to name just two. It may increase the essential oil content of herbs when planted among them. Yarrow has so many wonderful properties to it and is an ingredient in our own Golden Harvest Fertilizer.
Source: Companion Plants Web Link