New crop of hybrids blend practicality, aesthetics

WASHINGTON — Numerous newly hybridized plants are introduced every year with the goal of creating trees, shrubs and perennials that perform well, are hardy, pest-resistant and long-lived and that display practical and aesthetically pleasing characteristics. Here are some promising introductions.

First lady flowering cherry (Prunus X incam ‘Okame’) crossed with (P.campanulata) is a perfect example of a successful plant-breeding project and of the lengthy period required for development before a plant is introduced to the public. Bred at the U.S. National Arboretum in 1982 by Donald Egolf, first lady flowering cherry was developed for flower color and hardiness. One seedling proved to be outstanding, with deep rose-colored, almost red flowers, good cold hardiness and a distinctly upright growth habit. This small flowering cherry — which grows to 27 feet tall by 14 feet wide in 20 years — was named first lady in 1988, officially released in 2003 and registered with the International Registration Authority for Unassigned Woody Genera in 2004. This tree took about 22 years from first breeding to its introduction to the public.

Green giant arborvitae (Thujastandishii X plicata ‘Green Giant’) is an effective screen for property lines and dividing large properties into room-size spaces. Green giant has a tightly pyramidal to conical habit branching full to the ground, is evergreen with rich green color and grows vigorously. It has been widely grown and tested in commercial nursery production and has no serious pest or disease problems. It is an excellent substitute for Leyland cypress.

Conoy viburnum is a selection from the cross of V. utile with V. X burkwoodii ‘Park Farm Hybrid’ bred in 1968 by Egolf at the National Arboretum. Selected for field trial and propagation in 1976, Conoy was named and released in 1988. It is distinguished from other burkwood viburnum cultivars because of its compact spreading growth habit — four to five feet tall and seven to eight feet wide. It has fine-textured, densely-branched, evergreen foliage and persistent, abundant, glossy red fruit lasting about six to eight weeks in the fall. Its dark pink buds produce many creamy-white flowers in spring, and the foliage has a maroon hue in winter.

Knock Out roses are one of the most disease-resistant roses on the market, are easy to grow, do not require special care and have stunning flowers. Their generous bloom cycle — about every five to six weeks — continues until the first hard frost. Plants are winter-hardy and heat-tolerant throughout most of the United States.

Callicarpa dichotoma ‘Duet’ is an excellent edge-of-woods plant. Gary Bachman and W. Edgar Davis discovered a variegated sport of callicarpa dichotoma ‘Albifructus’ at Tennessee Technological University in 2000. The National Arboretum and Tennessee Technological University released duet jointly in 2006. Duet is the first dependably variegated beautyberry, selected for its yellow-margined, variegated foliage and tolerance to full sun. This deciduous, rounded shrub grows about 6 1 /2 feet high and wide in four years, producing white fruit in September that persists for one to two weeks after leaves drop. This white-flowering member of the verbena family has handsome, shiny leaves.

Pocomoke crapemyrtle (Lagerstroemia indicaX fauriei ‘Pocomoke’) is a dwarf crapemyrtle hardy to Zone 7. Pocomoke is the second in a series of true miniature hybrids, reaching a height of 19 inches and a width of 35 inches after eight years. This deciduous, densely branched, compact shrub is highly tolerant to powdery mildew, has small, glossy, dark green foliage in spring and maroon to bronze-red fall color.

Sparkleberry holly, a cross between Ilex serrata and I. verticillata, is a large deciduous shrub with a striking and long-lasting display of brilliant red winter berries. Planted in a massed grouping, sparkleberry will add brilliant color to the winter landscape. It is a female selection and requires a pollinator for good fruiting.

One of my favorite native ornamental grasses is blue switchgrass (Panicum virgatum). It is an excellent ground cover as a meadow-style planting or standing among other flowering perennials in a border of shrubs and flowers. Used as an accent in your garden, switchgrass is a good plant to use because it holds architectural interest well into winter and fits in with most mixed perennial gardens.