Dahlias for the home landscape

Department of Horticultural Science Horticulture Information Leaflet 8500 7/98 DAHLIAS FOR THE HOME LANDSCAPE Erv Evans, Extension Associate Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating. Dahlias, Dahlia variabilis, are a popular addition to the landscape because they have a wide height range ( 1 to 6 ft) and a variety of flower shapes and sizes (2 to 12 inches). Color range includes orange, pink, purple, red, scarlet, yellow, and white. Some flowers are striped or tipped with a different color. Dahlias begin blooming in early summer and continue to frost. Flower production may slow with high summer temperatures and moisture stress. Dahlias can be started from dormant tuberous roots, grown from seeds, rooted from cuttings, or purchased as transplants. Because dahlias are hybrids, plants grown from seeds do not completely grow true to type. To ensure cultivar consistency, buy tuberous roots of named cultivars and save the tuberous roots from year to year. For information on specific cultivars visit the American Dahlia Society web site: http:/ /www.dahlia.org. Types of Dahlias Dahlias are classified according to flower shape and arrangement of petals. Single¬ flowering dahlias have one row of petals, generally grow to 3 ft or less, and have flowers 4 inches or less in diameter. Types of single- flowering dahlias include: singles, orchid-flowering, anemone, and collaretts. Single-flowering dahlias have a ring of evenly spaced petals. Orchid-flowering dahlias are similarto single-flowering types, but the ray florets curl up along the edges. Anemone flowers have an extra ring of small petals. Double-flowering types have multiple rows of petals, grow taller, and have large flowers. Double-flowering types are also classified according to flower size and shape. Cactus dahlias have somewhat tubular shaped petals that curve backwards for over one- half of their length. Semi-cactus dahlias resemble cactus types but the petals are broad at their base and curve for less than half their length. Incurved cactus cultivars have petals that curl strongly towards the center of the flower. There are two types of decorative dahlias: formal and semiformal. Formal decorative types have broad, regularly arranged, pointed or rounded petals that curve back towards the stem. Informal decorative dahlias have long, irregularly arranged, often twisted petals. Ball dahlia flowers are usually 3 72 inches in diameter and ball shaped or slightly flattened. The quilled petals are blunt or rounded at the tip. Pompons are smaller version of ball dahlias with flowers less than 2 inches in diameter. Dividing — Dahlia tuberous roots should be divided before they are planted in the spring. The best time to divide is after the eyes have sprouted and the new growth is no more than an inch in length. The new shoots are tender and easily broken, so handle gently. Cut the clump into individual tuberous roots with a sharp knife. Each tuberous root North Carolina Cooperative Extension Service NORTH CAROLINA STATE UNIVERSITY COLLEGE OF AGRICULTURE & LIFE SCIENCES