Companion Plant
Companion planting is the gardening method of growing plants together that assist each plant's growth in some way, whether it is by keeping away pests, increasing uptake of nutrients, or encouraging pollination. And a little like people, some plants prefer to keep their distance from other plants so that they grow better and aren't stunted in their potential. This article provides the basics of getting started in companion planting.
Steps
- Understand the ways in which companion planting can help improve your gardening. There are a number of possible benefits, including:
- Flavour improvement – some plants can improve the flavor of other plants simply by being in close proximity with one another.
- Nitrogen fixation – some plants are very good at this, helping plants less able provided they are planted in close proximity.
- Pest control – plants that discourage certain pests and can guard plants that are normally attractive to these pests; or, the plants can attract beneficial insects that keep predators down.
- Pollination increase – some plants can attract pollinators well, and other plants close by benefit from the pollinators arrival.
- Disrupting generic planting – a way to prevent the problems that come with monoculture growing, by having plants that differ from the monoculture crop.
- Shelter or support – the interaction of companion plants can serve to either shelter or support other plants, including providing windbreaks, Make a Garden in the Shade, and even something additional to grow on.
- Decide on the reasons you want to use companion planting for. Once you know why you want to companion plant, you will be better placed to be able to make sound choices about the types of plants. Read through the list above to help direct your search for suitable companion plants, whether it be for pest control, shelter, crop disruption, or one of the many other reasons, or several combined.
- Be aware that some combinations are advantageous while others are disadvantageous for plants. Some plants will grow vigorously in the presence of other plants, while others may do very poorly. For example, rue is an herb that is commonly incompatible with a range of garden plants, and pine trees tend to secrete a chemical that deters the growth of anything else under their trunk. On the other hand, basil and tomatoes are known well as a match made in heaven! Knowing the incompatibility as well as the compatibility is equally important.
- Learn some of the more common companion plant combinations. The following table demonstrates which companion plants do well together, or which should be grown apart, along with explanations:
| Plant | Companion | Incompatible | ||
| Alfalfa | Practically pest and disease free; alfalfa is prized for its ability to fix the soil with nitrogen. It also accumulates iron, magnesium, phosphorous, and potassium. It has a long taproot that can penetrate most soils and improve them. | - | ||
| Make Amaranth Porridge | Corn and cabbage family; amaranth hosts predatory ground beetles; camouflages the odour of the cabbage family, thereby deterring predators | - | ||
| Make Chocolate Anise Truffles | Coriander; anise hosts predatory wasps that consume aphids | - | ||
| Apple | - | Black Walnut Tree, Hawthorn | ||
| Artichoke | Sunflower, tarragon | None | ||
| Asparagus | Tomato, parsley, basil, carrots | Chive, garlic, leek, onion | ||
| Basil | Beans, broccoli, Brussels sprouts, cabbage, cauliflower, collard, kale, marigold, pepper (capsicum), tomato, asparagus - with tomatoes and asparagus plants, it repels flies, aphids, mites and mosquitoes and can help with tomato hornworms and asparagus beetles. | Rue, sage | ||
| Beans | Most vegetables and herbs, carrots, cucumber, lettuce | Onions, garlic, sunflowers | ||
| Beetroot, beet | Lettuce, beans (except runner beans), kohlrabi, onions, cabbage family; adds minerals to the soil and adds magnesium if composted; garlic and mint help beets to grow better | - | ||
| Choose Herb Blossoms for Eating | Tomatoes, strawberries; deters tomato worms, adds trace minerals to soil, increases proximate plants disease resistance, enhances flavour of strawberries, self seeds | - | ||
| Broccoli | Basil, beans, cucumber, dill, garlic, hyssop, lettuce, marigold, mint, nasturtium, onion, potato, radish, rosemary, sage, thyme, tomato | Grapes, lettuce, rue | ||
| Cabbage family (includes broccoli, brussels sprouts, cauliflower, kale) | Aromatic herbs, celery, beets, onion family, chamomile, spinach, chard | Dill, strawberries, tomato, pole beans | ||
| Caraway | Good next to shallow rooted crops, loosens compacted soil with deep roots, flowers attract parasitic wasps | Dill, fennel | ||
| Carrots | Pea, lettuce, rosemary, onion family, sage, tomato; can benefit from being grown near flax | Dill, caraway, celery, parsnips | ||
| Sew a Catnip Mouse | Deters mice, flea beetles, Japanese beetles, squash bugs, weevils, ants, etc.; attracts cats | - | ||
| Celery | Onion and cabbage families, tomato, nasturtium , beans, leek, spinach | Parsnips, carrot, parsley, corn | ||
| Chamomile, German | Cabbages, cucumbers, onions (improves flavour), aromatic herbs; hosts hoverflies and wasps, increases oil production from surrounding herbs and tonic for all plants it grows near | - | ||
| Chives | Roses; prevent mildew, deters green flies and repels aphids | - | ||
| Protect Chrysanthemums from Wind | Kills bad nematodes, repels Japanese beetles (white flowers) | - | ||
| Clover | Grapes, apples; attracts beneficial insects, great for green manure, attracts predators of woolly apple aphid | - | ||
| Make Comfrey Compost | Avocado, fruit trees; accumulates calcium, phosphorous and potassium; can be used as a slug trap | - | ||
| Make Coriander Relish | Anise; deters spider mites, aphids, potato beetle | - | ||
| Corn, sweetcorn | Potato, beans, pea, pumpkin, cucumber, squash, climbing beans, amaranth, melons, peanuts, parsley, soybeans, sunflower, morning glory, white geranium | Tomato, celery | ||
| Cucumber | Beans, sweetcorn, pea, sunflowers, radish, celery, lettuce, dill, beets, carrots, nasturtium; when grown with sunflowers, the stems provide support for the cucumber vines | Potato (bad both ways), aromatic herbs, sage | ||
| Eggplant | Beans, marigold, garlic, pea, pepper (capsicum), potato, spinach, tarragon, thyme | Fennel | ||
| Garlic | Collard, raspberry, roses, apple trees, pear trees, cucumber, lettuce, celery; garlic accumulates sulphur (a naturally occurring fungicide); good against codling moths, Japanese beetles, root maggots, snails, and carrot root fly | Bean, pea | ||
| Grapes | Hyssop, basil, beans, peas, blackberries, chives, elms, mulberry trees; plant clover with grapes to increase soil fertility | Radishes, cabbage | ||
| Horseradish | Potatoes; deters potato bugs, blister beetles, and helps make potatoes more disease resistant | - | ||
| Hyssop | Cabbage, grapes; deters cabbage moths and flea beetles; can be used to encourage bees to return to their home (rub on the hive) | Radishes | ||
| Lavender | Fruit trees; flowers provide nectar, attract beneficial insects, deters whitefly and codling moth | - | ||
| Select and Use Leeks | Carrot; can repel the carrot fly | Legumes | ||
| Lettuce | Carrot, radish, strawberry, cucumber, spring onions (scallions), marigolds, beans, collards | Broccoli, fava bean, grains | ||
| Marigolds (Calendula) | A major pest deterrent: Keeps soil free of nematodes; discourages many insects. Plant freely throughout garden; known as the "workhorse of pest deterrents" Deters whiteflies. French marigold is less potent than Mexican marigold | Be careful using Mexican marigold near cabbages and beans as it can have a herbicidal effect; avoid planting marigolds next to beans at all | ||
| Marjoram | Improves flavour of all vegetables and many herbs | - | ||
| Melons | Corn, nasturtium, radish; oregano protects it from pests | Potato | ||
| Mint | Cabbage and tomatoes; deters white cabbage moths | Very invasive once starts growing, can crowd out other plants | ||
| Make Nasturtium Flower Sandwiches | Tomatoes, cabbage, cucumbers, and under fruit trees; deters wooly aphids, whiteflies, squash bug, cucumber beetles and other pests of the cucurbit family; attracts predatory insects | Radishes, cauliflower | ||
| Onion family | Beets, carrot, lettuce, cabbage family, summer savory, cauliflower, celery, chamomile, collard, cucumber, dill, kale, pepper (capsicum), potato, radish, rose, squash, strawberry, tomato; inter-crop with leeks and carrots to confuse carrot and onion flies; onions with strawberries help protect strawberries from disease | Beans, peas, asparagus, gladiolus | ||
| Oregano | Beans - enhances flavour; cabbage, broccoli, cauliflower, cucumbers, grapes | - | ||
| Make Parsley Pesto | Tomato, asparagus, rose | Mint | ||
| Pea | Carrots, radish, turnip, cucumber, corn, beans; peas fix nitrogen in the soil | Onion family, gladiolus, potato | ||
| Pennyroyal | Brussel sprouts, broccoli, cabbage; deters ants, aphids, ticks, fleas, and cabbage maggots | Poisonous to cats, do not plant where cats can access it | ||
| Pepper | Bean, carrot, marigold, marjoram, onion family, tansy, tomato | - | ||
| Petunias | Tomatoes and everywhere; repel asparagus beetle, leafhoppers, some aphids, Mexican bean beetles, tomato worms, other garden pests | - | ||
| Potato | Beans, corn, cabbage family, marigolds, horseradish; horseradish planted at the edges will of a potato patch will provide overall protection; comfrey will help protect from scab | Pumpkin, squash, tomato, cucumber, sunflower, fennel, kohlrabi, melon family, parsnip, swede/rutabaga, turnip; tomatoes can transfer blight | ||
| Pumpkins | Corn, melon, squash, marigold (deters beetles), nasturtium (deters bugs, beetles), oregano good overall pest protection | Potato | ||
| Radish | Pea, nasturtium, lettuce, cucumber, beans, cabbage family, carrot, chervil, collard, grapes, melon family, onion family, squash | Hyssop | ||
| Rhubarb | Cabbage family, beans (protects from black fly), columbine flowers, onion family, garlic, roses; deters red spider mite from columbines | - | ||
| Rosemary | Cabbage, beans, carrots and sage. Deters cabbage moths, bean beetles, and carrot flies | - | ||
| Rue | Roses, fruit, figs, raspberries (deters Japanese beetle), lavender. | Cucumber, cabbage, basil, sage | ||
| Sage | Cabbage, carrots, rosemary; repels cabbage moths, carrot flies, and ticks | Cucumber, rue, onion family | ||
| Southernwood | Cabbage, garden in general, virtually pest free but watch its crazy growth | - | ||
| Spinach | Strawberry, fava bean, beans, peas | - | ||
| Squash | Nasturtium, corn, marigold | Potato | ||
| Strawberry | Borage, beans, lettuce, onion, sage, spinach, thyme | Cabbage, broccoli, Brussels sprouts, cauliflower, kohlrabi | ||
| Summer savory | Onions, garlic, beans; enhances flavour of beans, onions, and protects from bean beetle; loved by honey bees | - | ||
| Sunflower | Beans, corn, squash; attracts hummingbirds which eat whiteflies; great as decoys for aphids away from corn | Potato | ||
| Tansy | Fruit trees, roses and raspberries. Deters flying insects, Japanese beetles, striped cucumber beetles, squash bugs, mice, and ants; can be invasive and is toxic for livestock | - | ||
| Tarragon | Plant throughout garden; few pests like it! | - | ||
| Grow Lemon Thyme | Cabbage; repels cabbage worms, flea beetles, whitefly, and cabbage maggots | - | ||
| Tomato | Onion family, nasturtium, marigold, asparagus, carrot, parsley, cucumber; basil improves flavour, growth and repels flies and mosquitoes | Potato, fennel, cabbage family, apricot, dill, black walnut tree (walnut wilt), corn (attacked by same worm), pole bean, kohlrabi | ||
| Turnip | Pea, onion family | Potato | ||
| Wormwood | Deters animals when planted as a border; deters black flea beetles, cabbage worm butterflies. | Peas, beans | ||
| Yarrow | Plant near aromatic herbs to increase production of essential oils; has natural insect repelling properties and is great for compost (speeds up break-down) | - |
Tips
- Aromatic herbs include: basil, thyme, oregano, chamomile, hyssop, mint, rosemary, sage, etc.
- Even with the knowledge that some plants benefit one another well, local conditions, soils, temperatures, etc., may impact on the extent of the effects. It is important to keep trying and observing to work out which combinations of companion plants work best.
- For plants that benefit from invasive growers such as mint, try using the clippings as mulch rather than crowding out the plants.
Warnings
- This is a guide. It is not foolproof and it is prudent for you to work out by trial and error what works for your own garden space. Some of the ideas may work, some may not, some may work differently from what you expect but give it a go and it's likely that you will be pleasantly surprised at the results gleaned from centuries of gardeners, farmers, and horticulturalists observing and sharing on this knowledge.
Things You'll Need
- Companion plants
- A plan with what you need from your companion planting
Related Articles
- Plant a Walnut Tree
- Grow Green Onions
- Kill Japanese Beetles
- Grow Broccoli
- Plant Marigolds
- Grow Marigolds
- Grow Basil
- Grow a Tomato Plant
Sources and Citations
The following sources contributed to the table:
- http://www.attra.org/attra-pub/complant.html;
- http://www.gardensablaze.com/Companions/CompanionYield.htm;
- Wikipedia, Companion Planting, https://en.wikipedia.org/wiki/Companion_planting
- Companion Planting, http://www.companionplanting.net/
- GrownUps, Companion Planting, http://www.grownups.co.nz/read/lifestyle/hobbies/companion-planting
