Dahlia 'Thomas Edison' Bulbs

'Thomas Edison' is a decorative dahlia that has long been a gardener's favorite, renowned for its tall stature, dramatic dinnerplate blooms, and its reliable, long-blooming, long-lived nature that you'll enjoy for years to come. Strong and vigorous, the 'Thomas Edison' dahlia grows to a mature height of between 36 to 48 inches and starts blooming in midsummer, continuing through fall, possibly to first frost. The exotic 9-inch flowers are fully double with broad, flat, slightly rolled petals arranged in a symmetrical pattern and saturated in a velvety rich-purple color. They are excellent cut flowers for monofloral bouquets or mixed floral arrangements. And you needn't worry about leaving the garden bare because the more you cut, the more they bloom. But the flowers won't open much after being cut, so harvest dahlias when the flowers are almost fully open.

'Thomas Edison' dahlia is a tuberous-rooted, tender perennial in Zones 9-11. Tall and bushy, it has an upright habit and may benefit from being staked or caged. 'Thomas Edison' makes a gorgeous accent or specimen, in garden or container, but is especially eye-catching when massed or grouped in the back of a garden border and beds.

Dahlias are easy to grow, but exact care may be Zone dependent. Generally, they grow best in a sunny to partially shady spot with rich, porous soil that drains freely, yet still holds enough water for the roots. Heavy clays that drain slowly or very sandy soils that do not hold water may need organic soil amendments, such as peat moss or ground bark.

Plant 'Thomas Edison' bulbs in spring after all danger of frost has passed, spacing tubers 12 to 36 inches apart and 3 inches deep in warm soil. Water thoroughly at planting and frequently while actively growing, making sure water reaches the roots. Pinch dahlias at 8 to 10 inches tall, cut back some of the taller stems, and fertilize in early spring and again in late summer to promote bushy foliage and abundant blooms. Mulch around plants to keep the soil cool and moist. Divide dahlias in fall.

Dahlia tubers can also be started indoors 4 to 6 weeks before the last anticipated frost date. Plant 1 'Thomas Edison' tuber per 5- to 8-inch pot filled with potting mix and place in a warm, sunny spot. Plant outdoors in spring after all danger of frost has passed.

NOTE: In Zones 3-7, the bulbs will need to be lifted before the first frost and overwintered inside, storing tubers at 50°F in dry peat moss or vermiculite. However, dahlias can be grown as annuals in all Zones.

Dahlias come in a wide variety of sizes, shapes, and colors. Dahlias are grown from tubers, which are similar to bulbs, so they're easy to plant. Follow our expert's advice on how to plant and care for dahlias in our Dahlia Care Guide. To learn more about dahlias, read our blog All About Dahlias.