Dahlias are beautiful flowers that bloom from mid-summer through fall, offering a range of colors from muted pastels to bright oranges and pinks. They are perennials that grow well in zones 8 and higher, but in colder climates, they need to be dug up and stored until spring. Learning how to plant dahlias tubers and grow tips on how to care for them can lead to gorgeous dahlias in your garden.
Delhi is a genus of tuberous plants that are members of the Asteraceae family. These plants include the sunflower, daisy, chrysanthemum, zinnia, and of course, aster.
Harvesting a flower from a dahlia plant is like pushing a button box. The flowers can range in size from petite 2-inch lollipop-style pom-poms to giant 15-inch “dinner plate” dahlias. Most varieties grow 4 to 5 feet tall. Plus, dahlias grow in a wide range of beautiful colors, including white, yellow, orange, pink, dark pink, red, dark red, lavender, purple and black, light blend, bronze, flame, dark blend, variegated and bicolor!
Tubers are planted in the ground in late spring and generally flower from July to the first autumn frosts. Dahlias are perfect for border gardens and make lovely cut flower arrangements. Growing vegetables? Put a row of dahlias on the border, where they will not shade your edibles.
Are you familiar with Dahlia perennials? These plants are considered a tender perennial in colder regions of North America. They are really winter hardy in hardiness zones 8 and higher. In colder zones, dahlias can either be treated as annuals or the tubers can be dug up after the first frost and stored indoors for spring. For gardeners in zones 6 and 7, it can vary and some have luck keeping tubers in the ground. (See what hardiness zone you’re in!)
Dahlias love moist, moderate climates and full sun. Though not well suited to extremely hot climates (such as southern Florida or Texas), Dahlias brighten up any sunny garden with a growing season that’s at least 120 days long.
Planting Dahlia thrives best when planted in 6 to 8 hours of direct sunlight and preferably in well-draining soil with a pH level of 6.0 to 7.5. Consider their size when planting and ensure that the soil has adequate organic matter or compost to lighten and loosen the texture for better drainage. They grow best in rich, loamy soil with enough moisture or water supply.
If you want to plant dahlias that appear wrinkled or rotten, look for pink buds or signs of green growth. To plant the tubers, start by digging a 6- to 8-inch deep hole. It also helps to mix some compost and a handful of bonemeal into the planting hole. Otherwise, do not fertilize at planting.
One way to support the growth and health of your plants is by using dwarf-size dahlias to border your garden. These dahlias are compact and won’t take up too much space, but they still provide beautiful blooms that add color and texture to your garden. A container that measures 12×12 inches is typically sufficient for these types of plants. So why not give your garden a little boost with some lovely dwarf dahlias?
When dahlias are established, water 2 or 3 times a week and more in hot, dry climates. Be prepared to tend to plants before or after rain, when opened blooms (especially large ones) tend to fill up with water or take a beating from the wind.
Recommended Varieties
There are approximately 60,000 named varieties and 18 official flower forms, including cacti, peonies, anemones, stellar, colarette, and waterlily. Here are some popular choices:
Gardening tips: Cut dahlias and they’ll bloom! For a bouquet, cut stems in the morning before the heat of the day and put them into a bucket of cool water. Remove stems’ bottom leaves and place the flowers into a vase of water. Check the water daily. Vase life is about 7 days.
Dahlias are hardy to Zone 8; in these more temperate regions, dahlias can simply be cut back and their tubers left in the ground through winter; covering with several inches of dry mulch. Other gardeners have had success storing dahlias tubers in dry mulch. In Zones 7, some gardeners claim their tubers survive winter in the ground; other gardeners have had varied results. It all depends on the severity of winter; native to Mexico, dahlias won’t survive freezing temperatures.
Ready for Summer? In spring, separate healthy tubers from the parent clump and discard wrinkled or rotted ones. Plant the survivors. Each tuber must have at least one “eye” or piece of the crown attached or it will not develop into a blooming plant. The eyes are little pink bumps at the base of the stem.
If this all seems like too much bother or you do not have the right storage place, skip it all and treat dahlias as annuals, buying new tubers in the spring.