Spider Dahlia

Buying

• Dahlias are available as tubers and plants at nurseries, dahlia societies and garden centers. Select large tubers without cuts, nicks or rot. Pick them up and gently squeeze them --- they should feel warm. Or purchase them online and have them shipped to your home. If you don't want to wait for the ground to warm up or the frost to melt away, start the tubers indoors about a month before the expected last frost, placing them where they can get good light. If you lose track of time, don't panic. You can plant them through the middle of June.

Planting Tubers

• Wait until the soil is warm before planting the spider dahlia tubers, as cool soil can stunt the flower's growth. Choose an area with full sun and work some compost down into the soil about 1 1/2 feet before digging a hole that's twice as deep as the spider dahlia tuber is long and just as wide. Set the tuber in the hole with the "eye" facing up, and fill it in with soil to the top of the dahlia's stem. If you're planting multiple spider dahlia tubers, place them 2 feet apart. As the plants grow, gradually cover the new growth in the hole with additional soil to support the stem.

Maintaining

• When the spider dahlias are actively growing and the soil in the hole is flush with the surrounding ground, begin watering them to encourage the roots to grow strong. They don't need much moisture, however. If it rains less than 1 inch per week, water your spider dahlias. Otherwise, let nature take care of them. Consider staking spider dahlias as they grow by placing one bamboo or plastic stake on both sides of each plant. Secure the lower stalk when the plants are young and secure the branches as the plants mature. Or use a tomato cage around your dahlias instead of staking them.

Controlling Pests and Disease

• Remove slugs when you notice them, especially in the morning, or use a slug killer. Look for Japanese beetles in the spider dahlia's blooms. If possible, pick them out and put them in a bucket filled with soapy water. Use insecticidal soap or pesticide to rid the flowers of pests if you don't mind chemicals. Some dahlias suffer fungal diseases that cause powdery mildew. Spray them with a fungicide in July and August to prevent the fungus from forming. Cut away infected leaves and branches if it has already formed.