Let's Stay Together: Companion Planting

Some aspects of organic gardening I'm unsold on. Sharryn asked me the other day about what plants might keep moths away from her property. I don't like to give people advice that I haven't seen work for me as a general rule. The plant she was thinking of was the citronella plant, but when it comes to dealing with insects, there are other, more tried and true methods that don't involve plants at all.

Companion planting, however, is something that I've seen work well in my own garden. For some reason, certain plants do well when they're grown in close proximity to other plants. There are quite a few herbs and flowers that give a boost to other plants, either by repelling harmful bugs, attracting helpful bugs, and just providing a better and more balanced ecosystem for everything living in your garden.

Companion planting is more an art than a science, though, and it won't solve every problem you have in your garden. Some plants are companions to specific other plants, and others are just good to have in just about any garden for their helpful contributions. In this post, I'll include only stuff that I have seen work firsthand in my own garden.

German Chamomile and just about everything —Called the "doctor plant" by some, chamomile provides a rather mysterious boost to almost any plant that grows in its vicinity. The flowers also play host to predatory wasps that will scour your beds for the harmful insects they feed on. Some gardeners like chamomile so much they make a weak chamomile tea and apply it to stressed-out plants that have been shocked by extreme temperatures, or are new transplants or seedlings.

(Above: German chamomile, an excellent companion plant)

Cilantro and Tomatoes — Because the fragrance of cilantro repels spider mites, a bug I've had trouble with on my tomatoes, cilantro will boost the health of your tomatoes by keeping away these sap-sucking jerks.

Peppers and most herbs — If you plant to do peppers this year, don't plant them away from your herb garden. Include them in that bed, and they will give a boost to parsley and basil. I have heard conflicting information on whether you should plant peppers near tomatoes, so go with your gut on that one.

Chives — Many members of the allium, or onion family, repel bugs with their scent. Chives are a good choice to grow if you want those benefits, but don't want to commit to garlic or onions (which have more restrictive growing seasons than the summer-friendly chive). Their flowers also attract helpful pollinators.

Mints — Members of the mint family, including spearmint and peppermint, are known to repel ants. Ants aren't usually a big problem in most gardens, but if you'd rather not have them crawling on you, consider plunking down some mint. Remember that mint can rapidly take over a garden, so try container planting.

(Above: Catnip, a member of the mint family, is repulsive to many bugs. Be careful though, as the plants spread out fast... and of course cats love the stuff)

Bee Balm and Lemon Balm — These weedy relatives of the mint family attract bees, which act as pollinators, and can improve the health and yield of your vegetables.

Sunflowers and Corn — It might be an old-wives tale, but sunflowers are supposed to grow well with corn. A more tangible benefit to sunflowers is that they will lure aphids away from your other plants. Their super-sturdy stalks can easily stand up to all but the most intense aphid attacks, and when the sunflowers start dropping seeds, they will attract birds that will also dine on aphids. Sometimes you can watch tiny ants "herding" aphids on sunflower stalks on particularly sunny days in summer.

(Above: Sunflowers provide a living trellis for plants to climb, and their flowers attract bug-eating birds, making them good companion crops.)

Sage and vegetables — The delicious Okie native sage pairs well with many vegetables, including cabbages, carrots, lettuce and broccoli. Rosemary also works together well with sage.

Basil and Tomatoes — Basil and tomatoes don't just go together in bruschetta. They're also a natural pair in the garden. The bright green annual herb will improve the flavor of your tomatoes. Basils of any cultivar are also good to plant next to petunias, asparagus, oregano and all kinds of peppers.

Marigolds — It's true that marigolds don't smell too nice. But that's because they have spent a long time in their native Mexico struggling to keep pests away. This makes them a good companion to lots of plants, plus they're just pretty to have to add a little color to your herb garden. They have also been confirmed to eliminate nematodes that are harmful to plant roots.

Beans, Squash and Corn — The American Indians of the Plymouth Bay area, as we all learned in history class, taught European settlers to grow the "Three Sisters" crops. This included corn, squash and climbing beans. Planted together in a single mound (in which fish were also buried for nitrogen-rich fertilizer), the plants each benefit the other, kind of like a paper-rock-scissors game where everybody wins. The beans fix nitrogen and climb the corn stalks. The spreading squash foliage acts as a mulch that crowds out weeds.

(Above: A plot planted with the Three Sisters crops)

Nasturtium — Nasturtium is a "trap crop" for aphids. The concept of a trap crop is it lures the pests, in this case aphids, away from other plants because the buggers like this particular plant so much. The gardener can then do with the bugs as he or she sees fit — up to and including uprooting the trap plant entirely and pitching it into an open flame. Die, suckers!

Keep in mind, this is just a sampling of what companion planting is all about. You can try all kinds of different combinations that aren't listed here. You should also be aware that some plants don't get along. There are "frenemy plants" too, so do a little of your own research and be aware of what those are.