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- Author or Editor: Donald R. Egolf x
Abstract
Man for centuries has had an appreciation of flowers made use of native plants, cultivated and selected more ornamental and exotic types, and improved food plants. But he has devoted relatively little research to the production of woody ornamentals -- trees and shrubs that have woody stems. The breeding of woody ornamentals, however, has gained momentum as a result of accelerated emphasis on beautification due to the population explosion and the aesthetic needs or urban sprawl.
Abstract
‘Shoshoni’ is a diminutive Viburnum plicatum Thunb. f. tomentosum (Thunb.) Rehd., double-file viburnum, with fine-textured foliage; masses of cream-white flowers; abundant, long-persistent scarlet fruit; and a dense growth habit. The common name is derived from the parallel rows of flat-topped inflorescences along the top of the horizontal branches. This is the 14th viburnum introduction by the U.S. National Arboretum (1–6).
Abstract
‘Tuskegee’ is the first Lagerstroemia indica L. × L. fauriei Koehne cultivar with dark pink to near red flowers and is the 4th U.S. National Arboretum mildew-(Erysiphe lagerstroemiae E. West.) resistent introduction from the controlled hybridization of the parental species. The 3 prior L. indica × L. fauriei introductions are ‘Muskogee’, NA 38448; ‘Natchez’, NA 38449; and ‘Tusca-rora’, NA 41787 (4, 5). In addition, 6 L. indica cultivars (‘Catawba’, NA 28861; ‘Cherokee’, NA 30167; ‘Conestoga’, NA 28862; ‘Potomac’, NA 28863; ‘Powhatan’, NA 28864; and ‘Seminole’, NA 30166) (2, 3), introduced by the U.S. National Arboretum, are highly mildew tolerant, but not immune.
Abstract
Malus × ‘Adirondack’ is a superior multiple-disease-resistant cultivar with a narrow obovate, upright-branched growth habit. Since there are relatively few crabapples with upright growth habit (i.e., ‘Centurian’, ‘Henningi’, Sentinel’ and ‘Silver Moon’) that have variable disease resistance or tolerance, ‘Adirondack’ is a significant introduction for nursery production. ‘Adirondack’, like ‘Naragansett’ (1), the first U.S. National Arboretum introduction, combines disease resistance and landscape characteristics.
Abstract
Pyracantha × ‘Apache’, the 5th U.S. National Arboretum introduction, combines disease resistance and compact dwarf growth habit. Pyracantha, commonly known as fire-thom, is a major nursery container-produced plant that is primarily grown for the spectacular fruit display. The four previously introduced cultivars are ‘Shawnee’, NA 28179 (1), ‘Mohave’, NA 32225 (2), ‘Navaho’, NA 38451, and ‘Teton’, NA 38450 (3).
Abstract
‘Apalachee’, ‘Comanche’, ‘Lipan’, ‘Osage’, ‘Sioux’, and ‘Yuma’ are the first intermediate growth habit Lagerstroemia indica L. × L. fauriei Koehne cultivars to combine mildew resistance, an array of spectacular exfoliating bark colorations, and a range of flower colors. Seven previously released U.S. National Arboretum-released L. indica × L. fauriei mildew-resistant cultivars, ‘Muskogee’, ‘Natchez’, ‘Tuscarora’, ‘Tuskegee’, ‘Biloxi’, ‘Miami’, and ‘Wichita’ are vaseshaped, outward-arched, small trees that can be expected to mature at 7 to 10 m high (4–6, 8); while four others, ‘Acoma’, ‘Hopi’, ‘Pecos’, and ‘Zuni’, are semi-dwarf growth habit cultivars that will ultimately mature at heights <3 m high (7). ‘Apalachee’, ‘Comanche’, ‘Lipan’, ‘Osage’, ‘Sioux’, and ‘Yuma’, with mature heights <5 m, bridge the landscape growth habit gap between the upright, small trees and the compact, semidwarf cultivars. With the introduction of these six cultivars, the U.S. National Arboretum Lagerstroemia breeding project has introduced 23 unique, distinct, and noteworthy cultivars for the nursery industry, landscape architects, and home gardeners alike (1–3).
Abstract
Viburnum japonicum (Thunb.) Spreng. × Viburnum dilatatum Thunb. ‘Chippewa’ and Viburnum lobophyllum Graebn. × V. japonicum ‘Huron’ are the first two semi-evergreen cultivars introduced that combine the heavy red fruiting of deciduous species with the evergreen characteristics of V. japonicum. Although the two cultivars have different parental species, the growth habits, flowering, fruiting, and foliage characteristics are similar. The most obvious difference is that ‘Chippewa’ (Fig. 1) has a broad obovate, lustrous leaf; whereas ‘Huron’ (Fig. 2) has a dull, more elliptic obovate leaf. ‘Chippewa’ and ‘Huron’ are the 16th and 17th Viburnum cultivar introductions from the U.S. National Arboretum shrub breeding project (1-7).
Abstract
Pyracantha × ‘Pueblo’ is the sixth disease-resistant cultivar introduced by the U.S. National Arboretum. Pyracantha, also referred to as firethom because of the brilliant, colored fruit clusters on a thorny plant, is one of the most showy berried shrubs in autumn. Firethom landscape merit is not restricted to the autumn and early winter but extends throughout the seasons with dense evergreen foliage that is further highlighted by profuse, cream-white bloom in early May. The previously introduced cultivars are ‘Shawnee’, NA 28179 (1), ‘Mohave’, NA 32225 (2); ‘Navaho’, NA 38451; ‘Teton’, NA 38450 (3); and ‘Apache’, NA 48240 (4).