List of companion plants


This is a list of companion plants, traditionally planted together. Many more are in the list of beneficial weeds. Companion planting is thought by its practitioners to assist in the growth of one or both plants involved in the association. Possible mechanisms include attracting beneficial insects, repelling pests, or providing nutrients such as by fixing nitrogen, shade, or support. Companion plantings can be part of a biological pest control program. A large number of companion plant associations have been proposed; only a few of these have been subjected to scientific testing. Thus where a table column for example states "Helps" or "Helped by", this is to be read as meaning that traditional companion planting involves putting the named plants in that column into an association with the plant named at the left of the row, with the intention of causing the one plant to help or be helped by the other. Mechanisms that have been scientifically verified include using strongly aromatic plants to deter pests; using companions to hide crops from pests; providing plants as nurseries for beneficial insects including predators and parasitoids; trap cropping; and allelopathy, where a plant inhibits the growth of other species.

For vegetables

Common nameScientific nameHelpsHelped byAttracts-Repels/+distractsAvoidComments
AlliumsAlliumFruit trees, nightshades, brassicas, carrotsCarrots, tomatoes, carrots and African spider plants together, marigolds, mintsThripsslugs, -aphids, carrot fly, -cabbage loopers, -cabbage maggots, -cabbage worms, -Japanese beetlesBeans, peasAllium is a genus of plants which includes onions and garlic.
AsparagusAsparagus officinalisTomatoes, parsleyAster family flowers, dill, coriander, tomatoes, parsley, basil, comfrey, marigolds, nasturtiumsOnion, garlic, potatoes
Beans, bushPhaseolus vulgarisCucumber, strawberriesCelery, strawberries, grainssoybeans, dry beans, alfalfa"Lettuce, potato, tomato, other legumes, crucifers, or cucurbits increase sclerotinia" in the soil and should be avoided before and after snap beans. See the entry for "Legumes" for more info
Beans, polePhaseolus vulgarisRadishes, Cornbrassicas, kohlrabithe stalk of the corn provides a pole for the beans to grow on, which then gives nitrogen to the soil of the corn. Beans and corn are traditional "Three Sisters" plants. As for Radishes, see the entry for "Legumes".
Beans, favaVicia fabaStrawberries, CelerySee the entry for "Legumes" for more info
BeetsBeta vulgarisbush beans, cabbage, lettuce, kohlrabi, onions, brassicas, passion fruitBush beans, onions, kohlrabi, catnip, garlic, mintRunner or pole beansGood for adding minerals to the soil through composting leaves which have up to 25% magnesium. Runner or pole beans and beets stunt each other's growth.
BrassicasBrassicaonions,Beets, spinach, chard, Aromatic plants or plants with many blossoms, such as celery, chamomile, and marigolds. Dill, sage, peas, peppermint, spearmint, rosemary, rye-grass, garlic, onions and potatoes. geraniums, alliums, nasturtium, borage, hyssop, tomatoes, thyme, wormwood, southernwood, beans, cloverWirewormsMustards, nightshades, pole beans, strawberriesBrassicas are a family of plants which includes broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, kohlrabi, radish, and turnip. Thyme, nasturtiums, and onion showed good resistance to cabbage worm, weevil and cabbage looper.
BroccoliBrassica oleraceaLettuceBeets, dill, onions, tomato, turnip, cloverBroccoli as a main crop intercropped with lettuce was shown to be more profitable than either crop alone. Turnip acts as a trap crop. See brassicas entry for more info
Brussels sproutsBrassica oleraceaSage, thyme, clover,
CabbageBrassica oleracea / Brassica chinensisBeans, celeryBeans, clover, calendula/pot marigold, chamomile, larkspur, nasturtiums, dill, coriander, hyssop, onions, beets, mint, rosemary, sage, thyme,Snails and slugsGrapesSee brassicas entry for more info. If using clover as an intercrop it should be sown after cabbage transplant so as not to affect crop yield. Nasturtiums repel cabbage moths
CarrotsDaucus carotaTomatoes, alliums, beans, leeks, lettuce, onions, passion fruitLettuce, alliums, rosemary, wormwood, sage, beans, flaxAssassin bug, lacewing, parasitic wasp, yellow jacket and other predatory waspsLeek moth, onion flyDill, parsnip, radishTomatoes grow better with carrots, but may stunt the carrots' growth. Beans provide the nitrogen carrots need more than some other vegetables. Aromatic companion plants repel carrot fly. Alliums inter-planted with carrots confuse onion and carrot flies. For the beneficial insect-attracting properties of carrots to work, they need to be allowed to flower; Otherwise, use wild carrot, Queen Anne's Lace, for the same effect.
CauliflowerBrassica oleraceaBeans, celery, spinach, peasMixture of Chinese cabbage, marigolds, rape, and sunflower. Spinach, peasSee brassicas for more info. See peas regarding their mutualism with cauliflower.
CeleryApium graveolensBush beans, brassicas, cucumberCosmos, daisies, snapdragons, leeks, tomatoes, cauliflower, cabbage, bush beansWhitefliesCorn, aster flowersAster flowers, can transmit the aster yellows disease
ChardBeta vulgaris ssp. ciclaBrassicas, passion fruit
Corn / MaizeZea maysBeans, cucurbits, soybeans, tomatoesSunflowers, dill, legumes, peanuts, cucurbits, clover, amaranth, white geranium, pigweed, lamb's quarters, morning glory, parsley, and potato, field mustard,Tomato, celeryProvides beans with a trellis, is protected from predators and dryness by cucurbits, in the three sisters technique
CucumberCucumis sativusBeans, kohlrabi, lettuceKohlrabi, nasturtiums, radishes, marigolds, sunflowers, peas, beans, chamomile, beets, carrots, dill, onions, garlic, amaranth, celery, Malabar spinachBeneficial for ground beetlesRaccoons, antsPotato, aromatic herbsSow 2 or 3 radish seeds in with cucumbers to repel cucumber beetles. One study showed a 75% reduction in cucumber beetles with the concurrent seeding of amaranth. Various sprays from lettuce, asparagus, Malabar spinach, and celery were found to reduce whiteflies. See cucurbits entry for more info
CucurbitsCucurbitaceaeCornCorn, grain sorghumCucurbits are a family of plants that includes melons, cucumbers, gourds, pumpkins, and squash
Eggplant or AubergineSolanum melongenaBeans, peppers, tomatoes, passion fruitMarigolds, catnip, redroot pigweed, green beans, tarragon, mints, thymeMarigolds will deter nematodes.
KohlrabiBrassica oleracea v. gongylodesOnion, beets, aromatic plants, cucumbersBeets, cucumbersSee Brassicas entry for more info
LeekAllium ampeloprasum v. porrumCarrots, celery, onions, tomato, passion fruitCarrots, clover,Swiss chardSee Alliums entry for more info
LegumesPhaseolus and ViciaBeets, lettuce, okra, potato, cabbage, carrots, chards, eggplant, peas, tomatoes, brassicas, corn, cucumbers, grapesSummer savory, beets, cucumbers, borage, cabbage, carrots, cauliflower, corn, larkspur, lovage, marigolds, mustards, radish, potato, peppermint, rosemary, lettuce, squash, lacy phaceliaSnails and slugsColorado potato beetleAlliums, gladiolasHosts nitrogen-fixing bacteria, a good fertiliser for some plants, too much for others. Rosemary and peppermint extracts are used in organic sprays for beans. Summer savory and potatoes repel bean beetles.
LettuceLactuca sativaBeets, beans, okra, onions, radish, broccoli, Carrots, passion fruitRadish, beets, dill, kohlrabi, onions, beans, carrots, cucumbers, strawberries, broccoli, thyme, nasturtiums, alyssum, cilantroSlugs and snails.Celery, cabbage, cress, parsleyBroccoli when intercropped with lettuce was shown to be more profitable than either crop alone.
MustardSinapis albaBeans, cabbage, cauliflower, fruit trees, grapes, radish, brussels sprouts, turnipsVarious pestsSee Brassicas entry.
NightshadesSolanaceaeCarrots, alliums, mints Beans, black walnuts, corn, fennel, dill, brassicasNightshades are a family of plants which include tomatoes, tobacco, chili peppers, potatoes, eggplant, and others
OkraAbelmoschus esculentusSweet potato, tomatoes, peppersBeans, lettuce, squash, sweet potato, peppersOkra and sweet potato are mutually beneficial when planted simultaneously.
OnionAllium cepaBeets, brassicas, cabbage, broccoli, carrots, lettuce, cucumbers, peppers, passion fruit, strawberries.Carrots, beets, brassicas, dill, lettuce, strawberries, summer savory, chamomile, pansyLentils, peas, beansSee Alliums entry for more info
ParsnipPastinaca sativaFruit treesA variety of predatory insectsThe flowers of the parsnip plant left to seed will attract a variety of predatory insects to the garden, they are particularly helpful when left under fruit trees, the predators attacking codling moth and light brown apple moth.
PeasPisum sativumTurnip, cauliflower, garlic,Turnip, cauliflower, garlic, mintsColorado potato beetlePeas when intercropped with turnips, cauliflower, or garlic showed mutual suppression of growth however their profit per land area used was increased.
PeppersSolanaceae, CapsicumOkraBeans, tomatoes, okra, geraniums, petunias, sunflowers, onions crimson clover, basil, field mustardBeans, kale Pepper plants like high humidity, which can be helped along by planting with some kind of dense-leaf or ground-cover companion, like marjoram and basil; pepper plants grown together, or with tomatoes, can shelter the fruit from excess sunlight, and raise the humidity level. Sunflowers, when in bloom at the right time, shelter beneficial insects, lowering thrips populations.
PotatoSolanum tuberosumBrassicas, beans, corn, peas, passion fruitHorseradish, beans, dead nettle, marigolds, peas, onion, garlic, thyme, cloverMexican bean beetleAtriplex, carrot, cucumber, pumpkin, raspberries, squash, sunflower, tomatoHorseradish increases the disease resistance of potatoes. It repels the potato bug. Garlic is more effective than fungicides on late potato blight. Peas were shown to reduce the density of Colorado potato beetles.
PumpkinCucurbita pepoCorn, beansBuckwheat, Jimson weed, catnip, oregano, tansy, radishes, nasturtiumsspiders, ground beetlesPotatoesRadishes can be used as a trap crop against flea beetles, cucurbita can be used in the Three Sisters technique. Nasturtiums repel squash bugs.
RadishRaphanus sativusSquash eggplant, cucumber, lettuce, peas, beans, pole beans,Chervil, lettuce, nasturtiumsflea beetles, cucumber beetlesGrapesRadishes can be used as a trap crop against flea beetles. Radishes grown with lettuce taste better.
SoybeanGlycine maxCorn, sunflowerA mixture of corn, mungbean, and sunflower was found to rid soybeans of aphids.
SpinachSpinacia oleraceaBrassicas, passion fruitStrawberries, peas, beansThe peas and beans provide natural shade for the spinach. See cauliflower notes regarding mutualism with spinach.
SquashCucurbita spp.corn, beans, okra,Beans, buckwheat, borage, catnip, tansy, radishes, marigolds, nasturtiumsSpiders, ground beetlesRadishes can be used as a trap crop against flea beetles, cucurbita can be used in the three sisters technique. Marigolds and nasturtiums repel squash bugs. Marigolds repel cucumber beetles.
Sweet potatoIpomoea batatasOkraOkraOkra and sweet potato are mutually beneficial when planted simultaneously.
TomatoesSolanum lycopersicumCelery, roses, peppers, asparagusAsparagus, basil, beans, bee balm, oregano, parsley, marigold, alliums, garlic, leeks, celery, geraniums, petunias, nasturtium, borage, coriander, chives, corn, dill, mustard, fenugreek, barley, carrots, eggplant, marigold, mints, okra, sage, thyme, "flower strips", cucumbers, squashAsparagus beetleBlack walnut, alfalfa, corn, fennel, chili peppers, peas, dill, potatoes, beetroot, brassicas, rosemaryBlack walnuts inhibit tomato growth, in fact they are negative allelopathic to all other nightshade plants as well, because it produces a chemical called juglone. Dill attracts tomato hornworm.

Growing tomatoes with Basil does not appear to enhance tomato flavour but studies have shown that growing them around 10 inches apart can increase the yield of tomatoes by about 20%. One study shows that growing chili peppers near tomatoes in greenhouses increases tomato whitefly on the tomatoes.
Cucumbers and squash can be used as living mulch, or green mulch, around tomato plants. The large leaves of these vining plants can help with soil moisture retention.
Turnips and rutabagasBrassica rapa and Brassica napobrassicaPeas, broccoliHairy vetch, peashedge mustard, knotweedTurnips act as a trap crop for broccoli. See peas regarding their mutualism with turnips.

For fruit

Common nameScientific nameHelpsHelped byAttracts-Repels/+distractsAvoidComments
AppleMalus domesticaClover, chives, garlic, leeks, nasturtium, southernwood, daffodils, comfreyCedar because of apple-cedar rust. Walnut because its roots produce growth inhibitors that apple trees are sensitive toFrench marigold inhibits codling moth but also its insect enemies, and fails to reduce damage to apples.
ApricotPrunus armeniacaPeppersA fungus that peppers are prone to can infect apricot trees causing a lot of harm.
BlueberriesVaccinium spp.Oak trees, pine trees, strawberries, clover, bay laurel, dewberries, yarrowtomatoes
Pine and oak trees create the acidic soil blueberries need. Strawberries and dewberries create healthy ground cover, clover fixes nitrogen for the blueberries' high needs, yarrow and bay laurel repel unhealthy insects. Each of the herbal companions listed also like the acidic soil the blueberry plant needs.
Fruit treesVariousAlliums, tansy, nasturtiums, marigolds, marjoram, lemon balm, mustards, dandelions, borage
GrapesVitis spp.Hyssop, basil, beans, chives, geraniums, mustards, oregano, clover, peas, blackberriesCabbage, garlic, radishes
MelonCucumis meloChamomile, pigweed, summer savoury, sow thistle
Passion fruitPassiflora edulisPotatoes, beets, Swiss chard, carrots, spinach, strawberries, eggplants, onions, leeks, lettuceCucurbits, maize, cowpea, sorghum, okra, sweet potatoes
PearsPyrus spp."Aromatic plants"
StrawberriesFragaria × ananassaBush beans, lettuce, onions, spinach, passion fruitCaraway, bush beans, lupin, onions, sage, thyme, borageSlugs and snails.Brassicas, Verticillium-susceptible species Thyme planted and/or placed next to each other help grow more strawberries quickly.

For herbs

Common nameScientific nameHelpsHelped byAttracts-Repels/+distractsAvoidComments
AnisePimpinella anisum CorianderBees, butterflies and hummingbirdsNot to be confused with star anise which is an entirely different species.
BasilOcimum basilicumTomato, peppers, oregano, asparagus, petunias, grapesChamomile, aniseSlugs and snails. butterfliesasparagus beetle, hornworms, mosquitoes, thrips and fliesCommon rue, thymeIs said to make tomatoes taste better, chamomile and anise are supposed to increase the essential oils in many herbs like basil
BorageBorago officinalisAlmost everything, especially beans, strawberry, cucurbits, fruit trees, tomatoes and cabbagePredatory insects, honeybeesMany pests, tomato wormPredict a square metre for its adult size. Borage is a good companion for a wide variety of plants.
CarawayCarum carviStrawberriesParasitic wasps, parasitic fliesDill
CatnipNepeta catariaEggplantFlea beetles, ants, aphids
ChamomileMatricaria recutitaMost herbs, brassicas, cucumber, wheat, onion, cabbageHoverflies, waspsGrowing near herbs will increase their oil production.
ChervilAnthriscus cerefoliumRadish, lettuce, broccoliAphidsRadishLoves shade, fortunately it grows well with shade-tolerant food plants; will make radishes grown near it taste spicier
ChivesAllium schoenoprasumApples, carrots, grapes, roses, tomatoes, brassica, many othersCarrotsCabbage worms, carrot fly, aphids, mites, nematodesBeans, peasSame companion traits as all alliums said to prevent apple scab after 3 years planting at base of apple trees
Cilantro / CorianderCoriandrum sativumAnise cabbage, spinach, lettuce, tomatoBeans, peasTachinid fly, hoverfliesAphids, spider mites, white flies and potato beetleAttracts hoverflies which may in turn reduce pest populations in cabbages.
DillAnethum graveolensBrassicas, cabbage, corn, fennel, lettuce, onions, cucumbersFennelTiger swallowtail butterflies/caterpillars, hoverflies, wasps, ladybugs, tomato hornworm, honeybees, ichneumonid waspsAphids, spider mites, squash bugs, cabbage looperCarrotsOne of the few plants said to grow with fennel: See fennel for info about intercropping.
FennelFoeniculum vulgareDillDillLadybugs, syrphid fly, tachinid flyAphidsFennel is allelopathic to most garden plants, inhibiting growth, causing to bolt, or actually killing many plants. When growing together a higher ratio of fennel to dill provides the highest profit. Dill has a stabilizing effect on the fennel seed. Because it attracts syrphidae it reduces aphids through predation.
FlaxLinum usitatissimumCarrots and potatoesColorado potato beetleFlax contains tannin and linseed oils which may offend the Colorado potato bug
GarlicAllium sativumVetch, brassicas, beets, roses, tomatoes, cucumbers, lettuce, celery, peas, potatoesTarragon, peasAphids, Japanese beetles, mites, cabbage looper, ants, cabbage maggot, fruit borers, red spider mites, slugsGrapesSee Alliums entry for more info. Peas and garlic when planted closely together suppress each other's growth; however the profit over land area used is higher. Tarragon makes garlic grow rapidly.
HyssopHyssopus officinalisBrassicas, cabbage, grapesHoneybees, butterflies, beesCabbage moth larvae, cabbage butterfliesRadishesStimulates growth of grapes.
LavenderLavandula angustifolia, L. dentata, L. stoechasChamomile, lettuce, brassicas, onions, tomatoes, oregano, thyme, marjoram, sage, rosemary, basil, lemon balm, squashbutterflies, hummingbirds, bees
Lemon grassCymbopogon citratusEggplantCutwormsReduces cutworms in eggplant in laboratory trials
LovageLevisticum officinaleBeansIchneumonid wasps, ground beetles RhubarbIs thought to improve the health of almost all plants, like borage and geraniums, is considered a "magic bullet" of companion planting
OreganoOriganum vulgareGrapes, tomatoes, peppers, pumpkin, many other plantsBasilHoverflies/SyrphidaeAphidsProvides ground cover and much-needed humidity for pepper plants if allowed to spread among them. Because it attracts syrphidae, it reduces aphids through predation.
ParsleyPetroselinum crispumAsparagus, corn/maize, tomatoesApple, asparagus, roseSwallowtail butterflies, wasps, fliesAlliums, lettuceSacrificially attracts insects that feed on tomatoes
PeppermintMentha piperitaAlliums, brassicas, cabbage, peas, tomatoesCabbage root fly, ants, cabbage looper, aphids, onion flyRepels cabbage flies, has same general companion properties as other mints
RosemaryRosmarinus officinalisCabbage, beans, brassicas, carrots, thymeBean beetleDeters cabbage flies, repels many bean parasites
SageSalvia officinalisBrassicas, rosemary, cabbage, beans, Brussels sprouts, carrots, strawberry, tomato, marjoramHoneybees, cabbage butterflyCabbage flies, carrot fly, black flea beetle, cabbage looper, cabbage maggot, repels many bean parasitesAvoid any member of the allium family and common rue
SouthernwoodArtemisia abrotanumBrassicas, fruit treesControls cabbage moths and malaria mosquitoes.
SpearmintMentha spicataAlliums, brassicas, cabbage, peas, tomatoesAnts, aphids, onion fly, cabbage root flyControls ants and aphids.
Stinging nettleUrtica dioicaChamomille, mint, broccoli, tomatoes, valerian, angelica archangelica, marjoram, sage & peppermintAphids
Summer savourySatureja hortensisBeans, melon, onionsAlso delays germination of certain foul herbs
TarragonArtemisia dracunculusMost vegetables, but especially eggplantIts scent is disliked by most pests, and this plant is also thought to have Nurse Plant properties, enhancing the growth and flavor of crops grown with it.
ThymeThymus vulgarisBrassicas, cabbage, eggplant/aubergine, potato, strawberry, tomato, Brussels sproutsHoverflies/SyrphidaeCabbage worm, cabbage weevil, cabbage looper, aphids,Because it attracts Syrphidae, it reduces aphids through predation.
WormwoodArtemisia absinthiumBrassicas, carrotsAntsWormwood should be used with caution around most vegetables since it contains toxins.
YarrowAchillea millefoliumMany plants, "Most aromatic plants."Predatory wasps, ladybugs, hoverflies, damselbugsAphidsMay increase the essential oil production of some herbs. Also improves soil quality, use the leaves to enrich compost, or as mulch. Because it attracts syrphidae it reduces aphids through predation.

For flowers

Common nameScientific nameHelpsHelped byAttracts-Repels/+distractsAvoidComments
AlyssumLobularia maritimaLettuceSyrphidae and most beneficial insectsAphidsBecause they attract syrphidae they help reduce aphids through predation.
Baby's breathGypsophila paniculataSyrphidaeAphidsBecause they attract Syrphidae, they help reduce aphids through predation.
Bee balmMonarda spp.TomatoBees
Californian poppyEschscholzia californicaSyrphidaeAphidsBecause they attract Syrphidae, they help reduce aphids through predation.
DianthusDianthus caryophyllusRoses, lavender, echinacea, aster, foxgloveSlugs
GeraniumsPelargonium spp.Roses, corn, peppers, grapesLeafhoppers, Japanese beetlesTomatoes, tobacco, eggplants and other nightshadesA 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
LarkspurDelphinium spp.Beans, cabbage
LupinLupinusCucurbits, brassica, lettuce, rosemary, dill, strawberry, roseSummer savory, roseHoneybeesTomatoes and other solanaceaeThis wildflower is a legume, hosting bacteria that fixes nitrogen in the soil, fertilizing it for neighboring plants. Same with marigold, planting nearby roses causes them to grow vigorously.
MarigoldTagetes patula, T. erecta, T. minutaMost plants, especially tomatoes and peppers, cucurbits 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. Stinking Roger has also been found effective against certain perennial weeds. Same with lupin, planting nearby roses causes them to grow vigorously.
NasturtiumTropaeolum majusBeans, squash, tomatoes, fruit trees, brassicas, radish cucumbersPredatory insectsAphids, asparagus beetle, cabbage looper, cabbage worm, carrot fly, cabbage weevil, Colorado potato beetle squash bug, Japanese beetle, Mexican bean beetle, striped pumpkin beetles, whitefly, cucumber beetles flea beetleCauliflowerTrap crops for aphids, is among the best at attracting predatory insects, deters many pests of cucurbits
PansyViola x wittrockianaAlliums, onions, rosesRosesBees, butterflies, antsAnts, snails, slugs, white butterflyA good and nice-smelling flower that really attracts ants. It is like the viola plant, but has two or three colors in flowers. Helps alliums and onions, which repels the white butterfly.
PetuniaPetunia x hybridaCucurbits, asparagusLeafhoppers, Japanese beetles, aphids, asparagus beetleIs a trap crop almost identical to geraniums in function
PhaceliaPhacelia tanacetifoliaPlants which are prone to aphids, especially lettuce, tomato, rosehoverflyThis plant attracts hoverflies and is good around plants which are prone to aphids.
RoseRosa spp.Chives, garlic, marigolds
SunflowerHelianthus annuusPeppers, corn, cucumber, soybeans, tomatoes, swan plantSwan plantAphidsPole beansWas grown as a companion for corn before modern Europeans arrived in the Americas, supposedly increases their production, ants herd aphids onto sunflowers, keeping them off neighboring plants. Works as a trap plant for thrips keeping them off of bell peppers. Planting near swan plants help sunflowers grow rapidly.
Swan plantGomphocarpus physocarpus, Asclepias physocarpa, milkweedSunflowerSunflower, basilMonarch butterflyAphidsPlants that attracts aphids and spider mitesAttracts the monarch butterfly during spring and summer. Basil repels pests that attracts by the swan plant like aphids.
Sweet peaLathyrus odoratusSweet alyssum, lobelia, roses, lavender, catmintBrassica, spinach, silverbeet and saladsBees, butterfliesAphidsAn annual climbing plant, which is like the edible pea. Makes a good decoration in your garden or fence.
TansyTanacetum vulgareBeans, cucurbits, raspberries and relatives, roses, corn, fruit treesLadybugs, honeybeesflying insects, ants, Japanese beetles, cabbage butterfly, cabbage maggot, asparagus beetle, carrot fly, striped cucumber beetles, Colorado potato beetle, cutworm, flea beetle, flies, imported cabbageworm, squash bugsToxic to people and many animals; do not plant it where livestock browse. Is reputed to repel herbivorous insects.
ZinniaZinniaBeans, tomatoes, peppersWhitefliesAttracts hummingbirds that eat whiteflies, attracts pollinators

Other

Common nameScientific nameHelpsHelped byAttracts-Repels/+distractsAvoidComments
AlfalfaMedicago sativaCottonAssassin bug, big-eyed bug, ladybug, parasitic waspsLygus bugsTomatoes, fava beansUsed by farmers to reduce cotton pests, a good crop to improve soil; fixes nitrogen. Alfalfa has some allelopathic effects to tomato seedlings.
PeanutArachis hypogaeaBeans, corn, cucumber, eggplant, lettuce, marigold, melon and sunflowerPeanuts encourage growth of corn and squash
Walnut treeJuglans spp.Many types of grass including Kentucky bluegrass.European alder, hairy vetch, crownvetch, sericea lespedezaApple trees, grassesBlack walnut is harmful to the growth of all nightshade plants, including Datura or Jimson weed, eggplant, mandrake, deadly nightshade or belladonna, capsicum, potato, tomato, and petunia.