Gardeners have long known that certain combinations of flowers and vegetables seem to help each other. The vegetables produce more or are protected from damaging insects. Flowers attract pollinating insects such as bees, moths and butterflies, and in some cases hummingbirds. Since fruiting vegetables such as tomatoes, peppers, cucumbers, peas and beans need to be pollinated to produce, the flowers do a doubly good job. This combination of flowers that protect or help vegetables is called companion planting.
Marigolds assist several different vegetables. Easily grown, these annuals add a bright cheery note to the garden's color scheme of yellow and orange. Marigolds range from petite bushes only 8 inches high to tall bushes of 18 inches with large flowers mostly in yellows. Start seeds outside as soon as the average last date of frost has past and the ground can be worked. Or start the seeds inside earlier and then transplant them outdoors. Marigolds don't mind the heat of summer.
Marigolds protect beans, melons, potatoes, squash and cucumbers from beetles; eggplant and tomatoes from nematodes.
Border the garden with marigolds or plant just around selected vegetables.
Nasturtiums are edible flowers, which is a bonus. They are easily started from seed but don't like to be transplanted. Soak the seeds for four to six hours, but no longer than overnight to get them germinated quickly. Nasturtiums are cool-season flowers and don't like the summer heat. They have round leaves and come in oranges, reds and yellows, sometimes variegated with another color.
Nasturtiums protect cabbage family plants (cabbage, broccoli, kale, Brussels sprouts and cauliflower) from aphids, bugs and beetles. They also protect beans from beetles and celery from bugs and aphids. Nasturtiums protect cucumbers from aphids and helps the cucumber's growth and flavor as well. This plant also helps growth and improves the flavor of radishes.
Borage is considered a medicinal herb as well as a flower. This plant has dark or light blue cup-shaped flowers on bushes growing to 15 inches high. Borage leaves and stems will stain hands a brown color that fades within a day or two. Borage helps strawberries resist pests and grow stronger—and protects tomatoes against tomato worms, helps the plant grow and improves flavor.
Borage is easily started from seed after the first frost. This plant is a summer flower and prefers warmer weather.