Using natural pest control methods keeps a garden healthy without relying on harsh chemicals. A 2005 study at the University of Illinois showed that bagworm-infested shrubs surrounded by flowering plants had 71 percent higher rates of parasitism on the bagworms than shrubs without flowers nearby. While buying predatory insects is an option, growing flowers that provide pollen and nectar is a more reliable way to attract beneficial insects like lady beetles, hoverflies, or predatory wasps. These predators help control pest populations in the garden naturally.
Beneficial insects need food and water to survive. Adults often have short lifespans and need nectar at the right time to feed, reproduce, and lay eggs. While the larvae of these insects are usually the ones eating garden pests, the adults require energy sources to keep the population going. Planting flowers that bloom continuously ensures there is always food available.
Water is just as important as food. Add a few stones to a birdbath so insects have shallow areas where they can safely access moisture. The shape of the flowers also matters. Many beneficial insect adults have small mouthparts. Growing umbel-shaped and daisy-shaped blooms makes it easier for them to access nectar and pollen.
Adding specific plants to the garden can increase the population of helpful insects. Some species act as hosts for beneficial larvae or provide essential nectar for adult insects.
- Dill (Anethum graveolens) — This tender perennial grows 3 to 5 feet tall and produces airy yellow flowers. It serves as a host plant for swallowtail butterflies and attracts lady beetles, lacewings, and ichneumon wasps.
- Goldenrod (Solidago spp. and hybrids) — Growing 1 to 6 feet tall, this plant features plumes, spikes, or long arching stems covered in small flowers from late summer to fall. It draws hoverflies and leatherwing soldier beetles.
- Pink Evening Primrose (Oenothera speciosa) — These single or double pink, white, purple, yellow or red blooms appear in early to late spring. The plant is cold hardy in USDA zones 3 to 8 and attracts tiphia wasps.
- Pot marigold (Calendula officinalis) — With daisy-shaped blooms in golden yellow, orange, pink, peach, cream or bronze from late spring to frost, this 12 to 24-inch plant draws lady beetles and hoverflies.
- Queen Anne’s lace (Daucus carota) — These white blooms appear in summer and can grow 36 to 48 inches tall. The plant is cold hardy in USDA zones 3 to 11 and attracts hoverflies, lacewings, and lady beetles.
- Sweet alyssum (Lobularia maritima) — This tender perennial forms a mass of white, purple or lavender flowers from late spring to frost. It stays low, growing 3 to 9 inches tall, and attracts hoverflies.
