Beneficial flowers for a vegetable garden to deter pests
Repel Bad Bugs
"Some plants exude chemicals from roots or leaves that act as natural pesticides that suppress or repel harmful pests," according to Washington State University Extension. Marigolds (Tagetes sp.) and dahlia (Dahlia coccinea or pinnata) can help to repel nematodes, a microscopic worm that attacks vegetation. For optimal benefit, plant the marigolds or dahlias in several areas along the perimeter of the garden and sporadically throughout the garden.
Dahlias can potentially reach 3 feet tall. Marigolds are fast growing flowers and can reach a height of 6 to 36 inches. If using tall varieties of either flowering plant, place on the west side of vining vegetable plants like cucumber or squash to offer some afternoon shade.
Nasturtium (Tropaeolum majus) helps to control aphids. Nasturtium can reach up to 18 inches tall and produces blooms of red, yellow, pink or orange. Petunia (Petunia x hybrida), which may reach 12 inches tall, has been found to help deter tomato worms in the garden when the flower is planted close to the tomato plant. Color options for petunia may include white, purple, pink, red or bi-colors.
Deter Cats or Rabbits
Flowers won't keep all cats and rabbits out of the garden, especially cats who have previously "visited" the garden unobstructed or very hungry rabbits. Some success in keeping cats and rabbits out of the garden may be achieved by surrounding the garden with plants whose fragrance is not appreciated by the animals, like lavender (Lavandula angustifolia) or common geranium (Pelargonium hortorum). Lavender also provides fragrant buds for use in potpourri or sachets. The plant grows up to 24 inches tall and wide, depending on the variety. Geranium, which can grow up to 18 inches tall and 24 inches wide, produces blooms of white, red, pink or salmon to add color to any vegetable garden.