Gardenia Companions for Pests

Companion Planting

• Plants may look like they’re just sitting in the soil taking in sunlight and water, but in reality their roots, foliage and flowers produce a range of chemicals that are waging a "constant battle against pests, as Cornell University describes it. Plants produce their own pesticides or chemicals that are toxic to pests, and they use scents to confuse or repel insects. Other plants act as hosts, creating a preferred source of food for pests and attracting them away from other plants such as gardenias. Some plants attract beneficial insects that either feed on or use harmful pests as hosts for their young, eventually killing them.

White Flies

• White flies resemble small, fuzzy pieces of cotton. They feed on gardenia foliage, leaving behind a sticky substance called honeydew, which promotes the growth of sooty mold, a black fungus on leaves. Companion plants that combat white flies include basil, marigold and nasturtium, according to the Alabama Cooperative Extension. All three plants have strong scents that deter white flies.

Gray Aphids

• Gray aphids also feed on gardenia foliage, leaving honeydew that causes black, sooty mold. These tiny bugs tend to congregate on the underside of leaves. Companion plants that repel aphids include strongly scented plants such as basil, chives, coriander, dill, garlic, mint and petunias. Nasturtiums and feverfew serve as trap plants for aphids, drawing them away from gardenias.

Nematodes

• Nematodes are tiny worms that live in the soil and feed on gardenia roots, causing damage. Companion plants for controlling nematodes include marigolds, which contain toxic substances in their roots that kill nematodes. Before planting a gardenia, grow a crop of marigolds or plant marigolds around existing gardenia shrubs. Other nematode control plants include chives and dahlias, reports Penn State Cooperative Extension.

Predator Attractors

• Attract beneficial insects such as predatory wasps, ladybugs, soldier bugs and assassin bugs to your garden by planting species they prefer. Attractive flowers include asters, bergamot, black-eyed Susan, daisies, purple coneflowers, sunflower and sweet alyssum. Attractive herbs and vegetables include angelica, borage, caraway, carrots, coriander, dill, parsley, angelica and parsnip. Plants with open, cup-shaped flowers also attract beneficial insects.