A Beginner's Guide to Growing Spectacular Dahlias

Dahlias are the stars of the late-summer garden, producing massive, colorful blooms perfect for bouquets. By mastering their planting cycle and seasonal care, you can enjoy these reliable perennials year after year. Here is how to grow them successfully in your own backyard.

Preparing Your Tubers Dahlias are tender perennials that cannot survive freezing ground temperatures. Wait until the soil has warmed to at least 60°F—typically two weeks after your last frost date—before planting. Dig a hole 6 inches deep and place the tuber horizontally with the "eye" (a small growth point) facing upward. Cover with 3 inches of soil; as the sprout emerges, fill in the remaining hole.

Providing Support Dahlias grow rapidly and their heavy blooms often cause stems to droop or snap during summer storms. Installing support early prevents damage.

1. Place a sturdy 4-foot garden stake into the ground immediately upon planting to avoid damaging roots later.
2. Use garden twine or soft plant ties to secure the main stem to the stake as it grows taller.
3. Pinching out the top 3 inches of the center stem when the plant reaches 12 inches tall will encourage bushier, more productive growth.

Always label your dahlia varieties at planting time; once they are harvested or cut back, it is nearly impossible to tell different colors and bloom shapes apart.

Managing Water and Pests These plants are thirsty. Provide deep watering at the base twice a week, aiming for 1 inch of water total, rather than frequent shallow sprinkling which encourages shallow roots. Watch for aphids or thrips on new growth, which can be easily managed with a gentle stream of water or insecticidal soap.

Lifting for Winter If you live in USDA zones 7 or colder, the ground will freeze and rot the tubers. After the first hard frost kills the foliage, cut the plants back to 6 inches tall. Carefully dig up the clumps with a garden fork, shake off excess soil, and let them dry in a cool, dark place for 24 hours. Store them in crates filled with barely damp peat moss or wood shavings in a location that stays between 40°F and 50°F throughout the winter. With the right start and careful winter storage, your dahlia patch will reward you with an even larger harvest next season.