Integrating flowers into a vegetable garden, often called companion planting, moves beyond simple aesthetics to functionally optimize the growing space. This technique harnesses the natural properties of certain blooms to create a more resilient and productive environment for food crops. Introducing flowers strategically helps establish a balanced garden ecosystem, reducing the need for chemical sprays. The objective is to leverage the flowers’ ecological benefits, such as defense against pests and the attraction of beneficial insects, ensuring the health of vegetable plants.
Flowers that Deter Pests
Certain flowers possess strong scents or chemical compounds that actively repel harmful insects, protecting vulnerable vegetables from damage. French marigolds are highly regarded for their ability to suppress soil-dwelling pests like root-knot nematodes, which severely damage the root systems of plants such as tomatoes and peppers. The roots release a natural compound called thiophene that is toxic to these microscopic worms.
Nasturtiums function differently, acting as a “trap crop” by being significantly more attractive to pests like aphids, cabbage white butterflies, and squash bugs than nearby vegetables. By concentrating the pests on the leaves, gardeners can monitor and manage the infestation away from their main crops. Chrysanthemums contain pyrethrin, a natural insecticide, which deters a wide range of insects including spider mites, ticks, and ants.
Other flowers use strong aromas to confuse pests and mask the scent of preferred vegetables. Geraniums are effective at deterring cabbage worms, corn earworms, and Japanese beetles from leafy greens. Similarly, the pungent fragrance of lavender helps keep away moths, fleas, and flies, providing a protective border.
Flowers that Attract Pollinators
A separate group of flowers draws in the beneficial insects necessary for fruit production and natural pest control. Open, shallow flowers are effective because they provide easy access to nectar and pollen for pollinators, including bees, butterflies, and hoverflies. Sunflowers and zinnias, especially single-petaled varieties, attract pollinators essential for fruiting crops like squash, cucumbers, and melons.
Borage, with its star-shaped blue flowers, is a powerful magnet for honey bees, native bees, and hoverflies, boosting pollination rates for nearby food crops. Allowing herbs like dill and fennel to bloom also supports beneficial predatory insects, such as parasitic wasps and ladybugs. These wasps lay their eggs inside pest larvae, providing an effective form of biological pest control.
Sweet alyssum, a low-growing annual, attracts hoverflies and parasitic wasps with its continuous supply of tiny, nectar-rich flowers. Hoverfly larvae are voracious predators of aphids, helping to protect brassicas and lettuce from infestation. Yarrow is another choice for attracting beneficial insects like lacewings and ladybugs, which are predators of soft-bodied pests.
Dual-Purpose and Edible Flowers
Some flowers provide ecological benefits while also offering a culinary harvest, maximizing the utility of garden space. The bright petals of calendula can be used to add color to salads and garnishes, while the plant attracts beneficial insects like lacewings. Similarly, the delicate, slightly peppery blossoms of nasturtiums are edible, offering a colorful addition to meals alongside their function as a trap crop.
Squash blossoms, the flowers of zucchini and pumpkin plants, can be harvested and cooked, often stuffed and lightly fried. Harvesting the male flowers provides a yield without sacrificing potential fruit, while unpollinated female flowers can also be consumed. Bee balm, or Monarda, produces tubular flowers with a spicy, minty flavor excellent in teas or salads.
The flowers of certain herbs offer a dual benefit, such as chive blossoms, which have a mild onion flavor that works well as a savory garnish. The vibrant flowers of pansies and violets are popular for decorating baked goods or floating in drinks. These dual-purpose plants increase the diversity and productivity of the plot simultaneously.
Strategic Placement and Maintenance
The effectiveness of companion flowers relies heavily on their placement within the vegetable garden. Intercropping, which involves mixing flowers directly among the vegetables, maximizes the confusion of scent-guided pests and ensures pollinators are close to the crops needing fertilization. Tucking marigolds at the base of tomatoes or peppers creates a localized barrier against nematodes.
Alternatively, planting flowers in blocks or borders around the perimeter can create a protective barrier and a concentrated “insectary” to house beneficial predators. When choosing placement, consider the mature size of the flower; tall varieties like sunflowers must be placed on the north side of sun-loving vegetables to prevent excessive shade.
Maintenance involves ensuring a continuous bloom period throughout the growing season by planting flowers that mature at different times or by succession planting annuals. Allowing herbs like dill to flower and go to seed ensures a steady supply of nectar for beneficial wasps and can lead to self-seeding. Avoiding pesticides on these companion flowers is necessary, as this would eliminate the beneficial insects the flowers are meant to support.