Holly plants provide gardeners with a wide choice of features, according to North Carolina's State University Cooperative extension's horticultural specialist, M. A. Powell. These attractive plants may be ground covers as small as 18 inches or trees exceeding 50 feet. Some are evergreen, and some deciduous. Round, conical, or columnar varieties offer numerous landscaping options. Holly plants work as specimen or group plantings, foundations, hedges or screens.
Foster holly (Ilex x attenuata 'Fosteri'), also called Foster #2, is an evergreen hybrid reaching 20 to 30 feet high and up to 20 feet wide. In April and May, its small white flowers contrast strikingly with its shiny, elliptical 2- to 3-inch dark green leaves. Bright red berry clusters ripening in autumn and remaining on the trees through winter give Foster holly four seasons of garden interest. Largely pest-and-disease resistant, the tree is tolerable to mites, scale, and leaf miners.
Plant it in full sun--for maximum berry production--to partial shade. Protect it from winter winds where temperatures drop to minus 10 degrees Fahrenheit or lower, advises the Missouri Botanical Garden. Give this self-pollinating tree well-drained, acidic (pH below 7.0) organically rich soil.
Dwarf Holly 'Jersey Male'
Evergreen dwarf holly (Ilex 'Jersey Male') is a densely mounding, 1-foot high shrub. Its branches have dark green, elliptical, glossy 1.5-inch leaves. In May, 'Jersey Male' has small white flowers. Although it doesn't produce berries, it pollinates dwarf female hollies including ' Jersey Sprite.' It's vulnerable to several pests and diseases, including spider mites, scale, leaf scorch and powdery mildew.
Use 'Jersey Male', suggests the Missouri Botanical Garden, in rock gardens, along border fronts, and as a container plant. It likes full sun to partial shade and well-drained, evenly moist, acidic soil. Provide afternoon shade where summers are hot, and winter protection where temperatures drop below minus 10 degrees F.
Winterberry (Ilex verticillata) grows wild in swamps and damp woods and along ponds and streams throughout eastern North America. A round, deciduous shrub, it stands between 3 and 12 feet high. Oval, 2- to 3-inch deep-green leaves occasionally provide maroon autumn color. Small white flowers bloom in June and July. Pollinated females produce late summer and autumn berries. The bright red fruit remains through the winter and sometimes into the following spring.
Largely resistant to insects and disease, winterberry infrequently develops leaf spot or powdery mildew. Plant it, advises the Missouri Botanical Garden, as a foundation shrub or massed in a border. It's a good addition to boggy areas. For best results, give it in full sun to partial shade and moist, organically rich, acidic loam. Exceptionally hardy, it tolerates temperatures as low as minus 40 degrees F.