Companion planting isn't a new practice in gardening. Skilled gardeners know that certain plants naturally discourage pests in vegetable and flower gardens. Planting companion specimens in the home landscape provides an alternative to the use of pesticides on plants. Companion planting requires careful selection and placement of plants to detract or attract various types of insects. Pairing plants in the landscape in this manner allows beneficial insects to control populations of nuisance pests.
Plants work in mysterious ways to aid each other in the garden environment. Some plants provide natural fertilizers to the soil when used as compost materials. Plants with strong smells or natural secretions can repel certain insects. The power of these plants lies in the benefits to their neighbors. Limiting the appearance of pests allows the entire garden to thrive in a healthy environment.
Gardeners use varying height plants to benefit neighboring plants in the garden environment. Taller plants assist in shading low-growing vegetables or flowering plants. This practice not only benefits the smaller plant but also allows the gardener to use space wisely in small gardens.
Predator vs. Prey
A host of insects occupy the typical garden space. The key to successful companion gardening lies in finding a balance between "good" and "bad" bugs. Planting cultivars that form habitats for beneficial insects helps right the balance in garden infested with aphids, nematodes, mites or thrips. Companion planting allows the gardener to create a predator vs. prey balance by creating an appealing home for the beneficial insects.
A few plants offer assistance with some of the most annoying bugs in the garden. Placing these companion plants may discourage insects from munching on tender foliage in vegetable or flower gardens. Marigolds emit a chemical in the root that discourages nematodes so the placement of this plant can be crucial to the health of its neighbors. Gardeners report that mint, garlic and onions repel aphids. Planting shallow neck flowers encourages beneficial insects to find a home in your garden. Flowers provide abundant nectar for predators and also attract bees for beneficial pollination.
Very little data exists on the validity of companion planting despite the truth that many gardeners have successfully used plants to increase the quality of crop and flower yields. For this reason, each gardener needs to experiment with various plant pairings to determine what works best in that location. See Resources for additional information on companion plant groupings.