The seemingly endless selection of dahlia varieties and types can sometimes become overwhelming even to the most practiced gardener. Choosing between single, double, cactus shape, or dinner plate types can be difficult, but keep in mind that all dahlias have the same growing requirements. These beauties need well-draining soil and moderate fertility. That also means that companion plants for dahlias need to be carefully vetted to determine if they can survive in the same growing conditions. Luckily, many shrubs, perennials, and annuals grow well with dahlias and can be combined to create a unique garden space.
Shrubs To Plant With Dahlia
Dahlias are most often grown as a specimen plant or in a cutting garden for fresh flowers throughout the summer and early fall. Planting dahlias alongside shrubs is not usual, but it can be done if all of the plants enjoy the same growing conditions. Make sure that any hedge or shrub growing near dahlias is not so large that it would cast shade on the plants all day. Dahlias need to have their heads in the sun to bloom well. Low-growing and clipped boxwood, yew, euonymus, or pittosporum hedges in a formal garden should provide dahlias enough sun and give the whole garden a very clean and organized appearance.
Perennials To Plant With Dahlias
Many perennials have a natural affinity for dahlias and can be used to complement the graceful and open shape of dahlias. Oriental lilies, peonies, and shasta daisies bloom earlier than dahlias and look great in a succession planting. Just as the peonies start to fade, the dahlias will be large enough to take over the performance for the rest of the growing season. Lower-growing salvia, gaura, and daylilies can be used to camouflage dahlias before they reach maturity. The salvia and gaura stay in bloom for months, adding color and movement to the garden border.
Annuals To Plant With Dahlias
Depending on which annuals you choose, dahlias can take on different looks and styles. For a romantic cottage garden, pair dahlias with lantana and salvia in soft pastel colors, which will help even the smallest garden border sing all summer long. For a tropical garden design, mix scarlet petunias, berry-colored lantana, and dark-leaved dahlia at the front of a bed. Add cannas and other seasonal tropical plants to add depth and a continuous punch of color.
Best Companion Plants For Dahlias in Containers
Single-flowered dahlias are small enough to plant in just about any container or window box. To make a real impact, follow the basic thriller-filler-spiller strategy as a guide. For a low and long planter or window box, use dahlias as a thriller plant at the back of the container. Plant filler plants such as annual euphorbia around the dahlia and finish the whole look off with a spiller plant such as calibrachoa, which can trail to soften the edges.
Plants Not To Grow With Dahlias
Plants that require very moist soil at all times like bog or aquatic plants will not make good planting partners for dahlias. Dahlia tubers can quickly rot in soils that have poor drainage or during periods of seasonal flooding. Cattails, flag iris, marsh marigolds, and rush reed plants thrive in soils that stay soggy all year long and make poor companions for dahlias.
Plants that prefer drier soils or desert climates also are not a great match with dahlia. Cacti, yucca, paddle cactus, or aloes grow in a different climate than dahlia and would rot if planted in the moisture-retentive and rich soil that dahlias crave.
Best Plants To Grow With Dahlias
Dahlias are at their happiest when they have plenty of direct sunshine and rich, loamy soil. Planting other basic annuals and perennials in the same bed as dahlia is guaranteed to make for a low-maintenance and long-blooming garden bed. Single-flower dahlias look great with salvia planted as the centerpiece alongside perennial and annual verbena in soft shades of pink and purple.