Dahlia - The Ultimate Growing Guide from Proven Winners®
Add long-lasting color to the landscape with these dazzling flowering plants
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Dahlia flowers capture the spirit of the high garden season, delivering an exuberant display of color from mid-summer into fall. With striking blooms in a wide range of colors, sizes, and forms such as anemone, ball, pompon, and dinner plate, these late-season stars shine when many other plants have faded.
Grown from tubers, dahlias produce hollow stems, prolific flowers, and lobed foliage in shades of green, purple, or black. Native to the temperate mountains of Mexico, they thrive in mild temperatures between 50 and 80 degrees Fahrenheit. They are perennial in frost-free zones but often treated as annuals in colder climates. In these regions, the tubers can be dug up and stored indoors to replant the following year. Read on for tips on how to grow dahlias, care advice, and top varieties to try.
GROWING AND CARING FOR DAHLIAS
How to plant: Dahlia plants grow from underground bulbs known as tubers. Plant in mid to late spring once the soil has warmed and is workable. Choose a site with at least 6 to 8 hours of direct sunlight and amended, well-draining soil. When planting dahlia tubers, space 1 to 3 feet apart, depending on the mature plant size.
- Loosen soil in the planting area.
- Amend with sand, peat moss, or steer manure to improve drainage and provide nutrients.
- Dig a hole 4 to 6 inches deep.
- Add a handful of bone meal to the planting hole and mix it into the soil.
- If tubers have sprouted, cut back to 1 inch of growth.
- Lay the tuber horizontally on its side, then cover the tuber with soil.
- Withhold water until tubers have sprouted. Once plants begin to grow, avoid overwatering to prevent tuber rot.
- New dahlia shoots are susceptible to slug or snail damage, so apply bait as needed.
- Install a stake or tomato cage for support.
Soil: Amend clay or compacted soil with peat moss to improve drainage and steer manure for nutrients. Use compost sparingly, as it may be high in nitrogen. Too much nitrogen can result in weak growth, fewer and smaller flowers, and weakened tubers. Avoid planting dahlia tubers in soil that has been treated with herbicides. For containers, use a high-quality potting mix.
Watering: Dahlias prefer moderate moisture, with soil that is not overly soggy or dried out. Hold off watering newly planted tubers until they sprout. Avoid overwatering and allow soil to dry out somewhat in between waterings. Irrigate around the base of plants rather than overhead to discourage powdery mildew on the foliage.
Pruning: Dahlia plants benefit from early pruning to promote a bushier habit and increase flower production. When pruning dahlias, wait until plants are at least 18 inches tall. Cut dahlias back to just above the third set of leaves. Avoid overhead watering after pruning, which can allow water down the hollow stems and cause tuber rot. When plants are flowering, deadhead regularly to remove spent blooms, which will put energy into producing new flower buds and extend bloom time.
Fertilizing: Use a low-nitrogen formula such as a bloom booster with roughly a 1-2-2 NPK (nitrogen-potassium-phosphorus) ratio. Apply fertilizer 30 days after planting and repeat monthly throughout the growing season. Containers will need more frequent fertilizing, as nutrients leach out more quickly. Fertilize container plants every 2 to 3 weeks.
Heather Blackmore of Here She Grows shares her experience on how to dig and overwinter dahlia tubers. | Erin Schanen of The Impatient Gardener says that growing dahlias may not be as hard as you think. Here are some of her growing tips. |
Overwintering dahlia tubers: In colder climates, dahlia tubers can be saved and replanted the following spring. Here’s how to properly dig, store, and care for them over the winter:
- Wait until the first hard frost kills and blackens the foliage.
- Leave the tubers in the ground for 1 to 2 weeks to harden off.
- Cut the dead stems back to 4 to 6 inches.
- Gently lift the tubers and rinse off excess soil.
- Trim away any damaged or rotting sections.
- Allow tubers to dry for a couple of days in a well-ventilated space.
- Store in boxes, crates, or breathable bags, covering with peat moss, sawdust, or pine shavings.
- Keep them in a cool, dark location (40 to 50°F), such as a basement or unheated garage.
- Prevent freezing, which will kill the tubers.
- Keep the storage material slightly moist, not wet.
- Check monthly. If tubers begin to shrivel, mist lightly with water.
- In spring, bring tubers out of storage and plant.
- Divide clumps in spring or fall using a sharp knife, ensuring each section includes a growth eye.
TRY THESE PROVEN WINNERS® VARIETIES
While many dahlias are traditionally grown from tubers, the Proven Winners® varieties listed below are typically sold as nursery-grown plants, ready to transplant into your garden or containers. These easy-to-grow starts let you enjoy the beauty of dahlias without the extra step of planting tubers.
Add some of these dazzling dahlia varieties to your yard:
 | Mystic Illusion (Dahlia hybrid) has deep purple-black foliage and single lemon-yellow star-shaped flowers with a dark center. The striking contrast can be seen even from a distance. This award-winning dahlia variety is mildew resistant, with a versatile growth habit suitable for borders or containers.
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 | Virtuoso® Dayglo Yellow™ (Dahlia variabilis) has an exceptionally long bloom time, with vigorous green foliage and large, double, bright yellow flowers. Plants are mildew resistant and versatile in containers, beds and borders. The sturdy stems hold up well in cut flower arrangements.
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 | Virtuoso® Pinkerific™ (Dahlia variabilis) produces large, double, soft pink flowers from summer into fall. Pollinators are attracted to the long-lasting blooms. Use in a butterfly garden, mixed border or containers.
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 | Virtuoso® Rad Raz™ (Dahlia variabilis) has double deep pink blooms, dark green foliage, and a vigorous growth habit. This eye-catching variety is useful as a focal point, in a cutting garden, or combined in containers with other annuals.
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 | Virtuoso® Classy Carmine™ (Dahlia variabilis) has exceptional garden performance, producing dense foliage and bright carmine-red double flowers that bloom throughout summer and into fall. Use as a focal point and in cut flower arrangements.
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 | Virtuoso® Vibrant Violet™ (Dahlia variabilis) is a stunning variety with rich violet-purple flowers that add long-lasting color to the landscape. Combine with complementary-colored yellow or orange flowers for stunning contrast. Use as a thriller element in containers, as an elegant focal point, or in cut flower arrangements.
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HOW TO USE DAHLIAS IN YOUR LANDSCAPE
Dahlias add long-lasting color to beds, borders and containers. Here are some ideas on how to use dahlias in your yard:
- Plant dahlias in a cottage-style border in combination with classic cottage garden plants for an exuberant, informal look.
- Devote an entire bed to a dahlia garden, planting them in rows and including varieties with different forms and colors.
- Fill gaps in a mixed border with dahlias for quick color. Taller varieties that can reach up to 5 feet tall can be planted towards the back, while dwarf forms 1 to 2 feet tall can be planted in front.
- Place a dahlia plant in a decorative container by itself as a captivating focal point, or in combination with other plants to add bright color to a sunny deck or patio.
- Mass dahlias in a bed by themselves, or in combination with other warm-season annuals such as canna lily, elephant ears, coleus and lantana for bright color all summer long.
- Plant a fall border with dahlias and other late-season bloomers such as asters, Joe pye weed, ornamental grasses, goldenrod and black-eyed Susan.
- Include dahlias in a cutting garden alongside other plants such as gladiolus, Shasta daisy, sunflower, zinnias and cosmos for colorful bouquets to display in your home.
- Plant dahlias in a row along a fence or property line as a colorful hedge.
- Use a dwarf variety to edge a border or pathway.
 PREMIUM DAHLIA BULBSProven Winners® is excited to offer a line of premium flowering bulbs available at The Home Depot® and independent garden centers across the US. This exclusive line features combinations, as well as a selection of highly sought-after, yet hard to find, individual varieties. Each collection has been carefully curated to provide home gardeners with the uniqueness, convenience and superior garden performance they expect. |
DAHLIA FAQs
Are dahlias perennials? Do they come back every year?
Dahlia tubers can survive from year to year with proper care. Since plants are frost sensitive, the green growth will die back after the first hard frost. In zone 7 or colder, dahlia tubers will not survive in the ground over the winter. Some gardeners grow dahlias as annuals.
When to plant dahlias?
Dahlias need warm temperatures in order to grow. Plant tubers in mid-to-late spring after all danger of frost has passed and the soil temperature has reached 60 degrees. Planting sooner when the soil is still cold and wet can result in tuber rot and failure to thrive.
Do deer eat dahlias?
Dahlias are not a preferred food source of deer, though plants may incur damage from grazing if other food sources are scarce. Learn more about choosing deer-resistant plants.
Do dahlias like sun or shade?
Dahlias perform best with at least 6 hours of full sun per day. In hotter climates, provide some afternoon shade.
Do you cut off dead dahlia blooms?
Removing spent dahlia flowers will encourage new growth and flower buds, resulting in more flowers and a longer bloom time. New flower buds and spent blooms can look similar, so take care not to remove the buds. Spent flowers will have a cone shape, while buds are more rounded. Cut flowers that are finished blooming back to the first set of leaves for a neater appearance.
Do dahlias do better in pots or ground?
Growing dahlias in pots is a good solution if you have limited space, poorly draining soil, or want to display them on a patio or deck. Choose small- to medium-sized dahlia varieties and provide a 12-to-16-inch container large enough to accommodate the tuber and roots. Make sure there are adequate drainage holes in the bottom of the pot. Dahlias in containers will need more frequent watering and fertilizing than those in the ground.
COMPANION PLANTS
Combine dahlias alongside other plants with similar cultural needs of full sun, well-drained soil and moderate water.
Create a colorful cottage-style garden with dahlias and other flowering plants such as:
- Meteor Shower® verbena
- ‘Firefly Peach Sky’ yarrow
- ‘Treasure Trove’ black-eyed Susan
- Upscale® ‘Pink Chenille’ bee balm
Combine compact Virtuoso® dahlia varieties in containers alongside:
- Luscious® Berry Blend™ lantana
- Illusion® Emerald Lace sweet potato vine
- Whirlwind® Blue fan flower
- Supertunia® Hoopla® Vivid Orchid™
For long-lasting summer color, plant a sizzling sunny border with dahlias and other plants such as:
- Toucan® Coral canna lily
- Rainbow Rhythm® ‘Storm Shelter’ daylily
- Color Coded® ‘Frankly Scarlet’ coneflower
- Meant to Bee® ‘Royal Raspberry’ anise hyssop
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