Pest control in the garden is essential for maximizing the growth and yield of your plants, but many people are hesitant to spray chemical pesticides because of their side effects. Instead, many gardeners opt to use companion plants as a pest control method.
Companion planting is the practice where plants are grouped to improve the health and growth of all plants involved. The symbiotic relationship is often used as a natural way to keep pests out of the garden. For pest control, one of the plants naturally repels garden insects for one reason or another.
Choosing to utilize companion plants is a fantastic way to minimize pesticide use in your garden while keeping all of your garden healthy and thriving.
How They Work
There are two different ways these helpful plants go about their business in your garden. First, many of them naturally repel nasty bugs due to their volatile compounds and the resulting odor. Second, other plants attract beneficial insects that come in and get rid of the bad guys.
Plants to Consider
Fortunately, many different plants work well as companion plants, helping aid in pest control. Herbs are very commonly used, as well as some vegetables and some flowering ornamentals. This diversity gives gardeners many options to choose from when planting, allowing them to choose plants that fit a certain aesthetic or serve more than one function.
What it deters: asparagus beetle, carrot fly, flies, mosquitos, whiteflies
A staple in tomato-based pasta dishes, basil is an excellent plant for beginners. Many people like growing it because of its easy-going nature and great culinary uses. It grows well outdoors when it receives at least 6 hours of sunlight daily and likes the soil to stay moist. Basil is cold sensitive and enjoys temperatures above 70℉.
What it deters: aphids, asparagus beetle, tomato hornworm
With its beautiful blue flowers, borage makes a great “trap crop” for a handful of nuisance garden pests. It always attracts pollinators such as honeybees and other beneficial insects like ladybugs and lacewings. Plants are drought-tolerant and fast-growing, needing little care. While the herb is technically an annual plant, it readily reseeds itself every year.
What it deters: ants, aphids, cabbage lopers, cockroaches, Colorado potato beetle, flea beetles, Japanese beetle, squash bugs, weevils
A member of the mint family, catnip is a hardy perennial typically grown for its euphoric side effects in cats. The essential oil that induces such effects also works exceptionally well as natural pest control, making it an excellent plant for your garden. Catnip loves plenty of direct sunlight every day and likes the soil slightly dry before watering.
What it deters: aphids, carrot fly, cucumber beetles, Japanese beetles, spider mites
Many of the onion family members, chives included, make excellent pest control plants in the garden because of their sulfur-based aromas. Pollinators and other beneficial insects are drawn to their stunning flowers, while bugs like beetles and aphids can’t stand the smell. They also help deter deer. Chives love full sun and prefer moist, not waterlogged, soil.
What it deters: aphids, Colorado potato beetle, spider mites
Cilantro is typically grown as an annual, enjoying the cooler seasons of spring and fall. Once air temperatures exceed 85°F, hormones within the plant trigger it to switch to reproductive mode, causing it to bolt. Cilantro grows quickly, is tolerant of light frost, and thrives when grown in the garden or containers.
What it deters: aphids, spider mites, squash bugs
Dill seeds and leaves are used in many dishes, and the aromatic nature of the plant helps ward off garden pests. Growing dill is easy and straightforward. They like deep soils because of their long taproots and prefer drier conditions. They do best in the spring and fall, as dill can bolt when temperatures get too high.
What it deters: aphids, bean beetle, fleas, Japanese beetle, potato bug, spider mites
Garlic is considered one of the best companion plants available for your garden. It is compatible with most plants and helps to deter both insect pests and fungal diseases. The bulbs grow best in well-draining soil and thrive in raised beds if you have them. Keep the soil slightly drier to avoid the bulbs rotting.
What it deters: aphids, blister beetles, caterpillars, Colorado potato beetles, whiteflies
Horseradish plants work exceptionally well to repel soft-bodied insects in the garden, protecting neighboring plants. However, it does grow quickly and easily gets out of control, so it’s best to keep it in containers or raised beds. Horseradish prefers moist, silty soils and grow well in either full sun or partial shade locations in the garden.
What it deters: bean beetles, cabbage moths, carrot fly, ticks
Grown as a perennial shrub in many parts of the United States, lavender wards off insects with its revered scent. Lavender love hot, dry conditions, though, so they may not grow well in cool or humid climates. Allow the top couple of inches of soil to dry out completely before watering, and forego any fertilizer applications.
What it deters: most insects, including bean beetle, nematodes
Marigold plants deter most insect pests, flying or crawling critters, because of their naturally pungent aroma (especially French marigolds). They also work to help control in-ground pests as well. The plants contain a phytotoxin that repels nematodes in the soil, making them especially helpful next to tomatoes. In addition, they like moist, well-draining soil and full sun.
What it deters: ants, aphids, cabbage moths, flea beetles
Mint plants are some of the most commonly grown herbs, especially spearmint and peppermint. Their broad leaves release a distinctive menthol-based smell when brushed against or bruised. Plants tend to spread and take over, so they grow best in containers or raised beds that can keep them in check.
What it deters: ants, bean beetle, squash bugs, striped pumpkin beetles
Nasturtium plants work well to deter cucurbit pests while also shading out weeds in the garden. They also attract many pollinators and draw in hoverflies that prey on problematic insects like aphids. In addition, nasturtiums are easy to grow. Nasturtium do well in containers, raised beds, or in-ground as long as they are watered regularly.
What it deters: cabbage moths
Oregano flavors many Mediterranean and Mexican dishes, quickly gaining popularity in both indoor and outdoor herb gardens. When grown outside, they are perennials, coming back year after year. Oregano prefers well-drained soils and little to no fertilizer. Allow the soil to dry out before giving it more water.
What it deters: ants, fleas, flies, gnats, mosquitos
Pennyroyal acts as a natural pest control method, protecting neighboring garden plants and the humans and animals in the vicinity. Bright purple flowers also attract pollinators. It grows well next to all plants, preferring loamy soils and full sun. It is considered moderately invasive under ideal conditions, so keep an eye on it to prevent spreading.
What it deters: bean beetles, cabbage moths, carrot fly, mosquitos
Rosemary’s strong aroma works well as a natural pest control. They grow as perennial evergreen shrubs outdoors and need at least 6 to 8 hours of direct sun daily. They prefer well-drained soils and like the ground to dry out slightly before receiving more water. Since rosemary grows slowly, there is no need to fertilize.
What it deters: cucumber beetles, flea beetles, Japanese beetles
A short-lived, woody perennial rue is fantastic at deterring different types of beetles. It isn’t picky about soil type and prefers a spot where it receives full sun or light shade during the most intense part of the day. Avoid planting it near basil, cabbage, cucumbers, or sage. Rue is drought tolerant.
What it deters: bean beetles, cabbage moths, carrot fly
Garden sage is commonly grown for its culinary role in holiday dishes like turkey and stuffing. Its intense flavor and aroma naturally deter garden pests. They need full sun and prefer the soil to dry out slightly between watering. Harvest foliage lightly the first year to allow this perennial to reach its full size.
What it deters: ants, beetles, cabbage moths, Colorado potato beetle, cutworms, flies, squash bugs
Once popular as a culinary herb, tansy is primarily planted in the garden as a natural pest deterrent for many insect pests. When the leaves are brushed against or blown in the wind, they release natural compounds that give it a distinct aroma that deters bugs. In addition, they grow well from seeds in full sun or light shade.
What it deters: cabbage moths, cabbage worms
Thyme makes an excellent ground cover, bearing heady aromatic leaves on a low-growing evergreen. It hates having its root soggy, so allow the soil to dry out between waterings. Regularly pinch the tops off and prune the woody stems back to encourage full, bushy growth. The leaves are great for seasoning soups, stews, and meat dishes.
What it deters: asparagus beetle
Not only are tomatoes a popular garden plant because of their fruits, but they also make a great companion plant for pest control. The leaves are highly aromatic, helping to ward off nuisance bugs. Tomatoes grow best in full sun but will tolerate partial shade. Keep the soil around their roots evenly moist without being soggy.
What it deters: aphids, black flea beetles, cabbage worms, carrot rust flies, white cabbage butterflies
The strong scent emitted from wormwood works well to deter some of the most damaging garden insect pests. It works best as a companion plant around flowering ornamentals. If planted near vegetables or herbs, grow them in containers to keep the scented compounds from entering the soil. Raw wormwood is toxic and shouldn’t be planted around pets or small children.