Companion Plants for Dahlias

Marigolds

• Garden Hobbies calls marigolds some of the most popular flowers in the garden, due to their flexibility and bright, sunny blooms. According to Gardens Ablaze, marigolds also serve a purpose: they repel nematodes, aphids, cabbage maggots, potato and cucumber beetles, horn worms, white flies and even rabbits. Plant these flowers as a border around your dahlias, or interspersed among the more sensitive plants, to drive away pests that would normally prey on leaves and petals. Marigolds require full to partial sun, rich soil and plenty of moisture, and grow well under dahlia conditions.

Garlic

• Garlic drives away snails, slugs, cabbage maggots, beetles, Japanese beetles, mosquitoes, rabbits and ticks, states Gardens Ablaze. This root crop is a common companion plant in both vegetable and flower gardens, used as a protective border against crawling insects. Plant garlic around the edges of your dahlia bed to keep snails and slugs out. Put individual cloves in quick-draining, slightly dry soil in areas that get full sun. Garlic will grow year round, regardless of season.

Rosemary

• Rosemary brings a strong, clean scent to the flower garden while driving away snails, slugs, moths and beetles. Use this herb as a border or interspersed through the dahlias to give them more protection from snails and slugs. Plant rosemary in quick-draining soil mixed with sand, in areas that get full, bright sunlight. Rosemary grows year round under the right conditions, and gives gardeners fresh herbs for their kitchen while protecting the flowers.