Companion Planting
COMPANION PLANTING
Many plants have natural substances in their roots, flowers, leaves etc. that can alternately repel (antifeedents) 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 through out 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.
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.
PLANT GUIDE
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.
BASIL:
Plant with tomatoes to improve growth and flavor. 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.
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. Companions are lettuce, onions and brassicas.
BORAGE:
Companion plant for tomatoes, squash and strawberries.
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. Borage may benefit any plant it is growing next to via
increasing resistance to pests and disease. After you have planred this
annual once it will self seed.
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.
Tricky to establish. The flowers attract a number of beneficial insects.
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. Likes shade.
CHIVES:
Improves growth and flavor of carrots and tomatoes . Chives
may drive away Japanese beetles and carrot rust fly. Planted among apple
trees it may help prevent scab. A tea of chives may be used on cucumbers
to prevent downy mildew. 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.
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.
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.
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.
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 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 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"clocks are also
poisonous to humans. Please be careful where you plant them if you have
children. They are a beautiful annual plant grwoing 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. Has some
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!
GOPHER PURGE:
Deters gophers, and moles.
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 antifungal properties when a tea is made from it.
HOREHOUND:
Stimulates and aids fruiting in tomatoes.
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.
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.
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 menatode
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.
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.
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.
OPAL BASIL:
An annual herb that is pretty, tasty and said to repel
hornworms!
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 curcurbit 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!
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.
PARSLEY:
Plant among and sprinkle 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. Parsley increases the fragrance of
roses when planted around their base.
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, 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.
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.
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.
RADISH:
Plant radishes with your squash plants. Radishes may protect
them from squash borers! Anything that will help prevent this is worth a
try. Planting them around corn and letting them go to seed will help fight
corn borers.
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.
RUE:
Deters Japanese beetles in roses and raspberries. To make it even
more effective with Japanese beetles: crush a few leaves to release the
smell. Repels flies and has helped repel cats for us. Some say you should
not plant it near cabbage, basil or sage. A pretty perennial with bluish-gray leaves. May be grown indoors in a sunny window.Rue can cause skin irritation! Remedy: See cats and dogs: Rue spray.
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 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. A delightful plant that is virtually pest free.
SUMMER SAVORY:
Plant with beans and onions to improve growth
and flavor. Discourages cabbage moths. 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.
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.
WHITE GERANIUMS:
These members of the pelargonum family draw
Japanes 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.
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.