Never Grow Dahlias Next To These Water-Loving Flowers

The kaleidoscopic flowers of the 50,000 varieties of dahlias (Dahlia spp.) bloom in every color of the rainbow except green, brown, and true blue, and in every size and form imaginable. While they can require a little more care than other herbaceous perennials, their showy presence from midsummer through mid-fall makes them the stars of the garden. Dahlias prefer moist, well-drained soil but will suffer in consistently wet earth or standing water. Therefore, they won't do well alongside flowers like irises (Iris spp.), lily of the valley (Convallaria majalis), or forget-me-nots (Myosotis scorpioides), which are water-loving plants that prefer wet conditions. Dahlias also don't do well when they have to compete with trees for sun, water, or nutrients.

Dahlias are hardy in USDA zones 7 through 10. In hot climates, like that of their native Mexico, dahlias can be left in the ground over winter, but in cooler areas, the dahlia tubers need to be dug up and stored over the winter at 35 to 45 degrees Fahrenheit. They can then be replanted in spring. Plant dahlias in full sun or partial shade in soil with a high organic matter content. Stake them if you've chosen a tall variety, and water them during extended dry periods. Dahlias need disbudding, a process in which select healthy buds and blooms are removed, in order to form the perfect flowers that attract pollinators to your garden.

There are hundreds of flowers, trees, and bushes that won't coexist with your dahlias simply because they have different water requirements. Try picturing a plant in its native habitat when you're choosing flowers for your garden. Does that plant normally grow in a marsh or alongside a creek? If it does, it's probably one you should avoid. Some are not so obvious, and some might be a surprise, but as long as you choose plants at the nursery that require well-drained soil as dahlias do, full or partial sun, and good soil, you should be successful.

Irises are one of the most popular garden flowers but may not be a good match for your dahlias. In particular, Louisiana irises, a group of iris hybrids, include the small Iris brevicaulis and the 6-foot-tall Iris giganticaerulea, or giant blue flag iris. Consider these for planting in and around your garden's water feature. Siberian flag (Iris sibirica) is another iris that makes a good choice for a water feature.

Lily of the valley does best in shady areas and under bushes, and while it can survive occasional dry conditions, it thrives in a moist environment that would cause damage to dahlias. Once established, this rhizomatous perennial becomes a ground cover with delicate bell-shaped white flowers. Meanwhile, forget-me-nots, with their small blue, white, or pink flowers, require consistently moist soil and will tolerate wet conditions. Both lily of the valley and forget-me-not would do well in a woodland garden.