Fosteri Hybrid Holly Ilex x attenuata 'Fosteri'

Foster Holly is a cultivar of Ilex x attenuata and is an evergreen shrub or small tree that has a fine texture, and a dense, slender, conical, or pyramidal shape. It is slow-growing and may reach up to 20 to 30 feet tall and 10 to 15 feet wide. Its leaves are typically spiny, elliptical, and dark olive green. In the spring, small, fragrant, white flowers emerge. An abundance of small, pea-sized orangish-red-to-red berries ripen in the fall and persist through the winter.

Ilex x attenuata is a naturally occurring hybrid cross of Ilex cassine (Dahoon) and Ilex opaca (American Holly). It was initially found growing wild in Florida in the 1920s but is now found throughout the southeastern United States where both parents are native.

'Fosteri' or Fosters Holly, is a cultivar of the Ilex x attenuata. This cultivar represents a group of seedlings that were selected by E.E. Foster of Foster Nursery in Bessemer, Alabama in the 1950s. They are known as the Foster Hybrid Group, and 'Fosteri' is just one of the cultivars in this group.

The genus name, Ilex, is derived from the Latin name, Quercus ilex, for the holm oak whose leaves resemble the leaves of the shrubs in the genus Ilex. The hybrid name, attenuata, means narrowing to a point. This most likely refers to the growth habit of this hybrid.

Foster's Holly grows best in acidic, medium moisture, well-drained soils in full sun to part shade. Although the best fruit production occurs in full sun, these plants do well with some afternoon shade in hot summer climates. You should site the plant where it can be protected from cold winter winds and the soil is well drained. Mulch helps retain soil moisture and deter weed growth. Prune in the winter to maintain a desired size, although keep in mind that the plant flowers are on new growth. Plants can suffer from the cold in USDA Zone 5 and below.  This plant is moderately salt tolerant, air pollution tolerant, and mildly resistant to damage by deer. 

The plants of this species are dioecious, meaning that they have separate male and female plants. The female plant requires a nearby male pollinator plant to produce fruits. Foster's Holly is the rare holly in which female plants produce fruit without fertilization from a male pollinator. Botanically speaking, it is parthenocarpic (from Greek, parthenos meaning virgin, and karpos meaning fruit). Therefore, it is unnecessary to purchase a male foster holly for fruit.

The Foster Holly is ideal for the home landscape as a hedge or screen. It may also be used as a specimen, in small groups, or as foundation plantings. The evergreen foliage and heavy fruit set will add winter interest to your home garden.

Seasons of Interest:

Bloom:  Spring               Foliage:  Year-round          Fruits:  Fall and Winter

Quick ID Hints:

• finely textured, narrow, conical, or pyramidal-shaped broadleaf evergreen holly
• smooth, silver-gray bark
• alternate, elliptical, dark olive green leaves, 1.5 to 3 inches long with tiny, spiny marginal teeth (1 to 4 on each side of the leaf)
• small fragrant white flowers in the spring
• orangish-red to red drupes about 0.75 inches in diameter in the fall and winter

Insects, Diseases, and Other Plant Problems: Foster Holly has no serious insect pests or disease problems. Potential insects include holly leaf miners, spittlebugs, spider mites, whitefly, and scale. It is susceptible to leaf spot, leaf rot, tar spot and powdery mildew, leaf drop, leaf scorch, and chlorosis (yellowing of leaves in high pH soils).

The Clemson Cooperative Extension Home and Garden Information Center has a factsheet on common diseases and insect pests.

VIDEO created by Andy Pulte for “Landscape Plant Identification, Taxonomy, and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.

More information on Ilex x attenuata.