Ilex x attenuata 'Fosteri'

Ilex x attenuata, or Topal Holly, is a naturally growing evergreen shrub or small tree that is a hybrid cross of I. cassine (Dahoon) and I. opaca (American Holly). It was initially found growing wild in Florida in the 1920's, but is now found throughout the southeastern United States where both parents are native. 'Fosteri' or Foster's Holly, is a cultivar of I. x attenuata and, like its parent, is a small evergreen tree that is densely pyramidal and grows up to 20 feet tall (slightly smaller than the 25 foot parent). It is fast growing and is a heavy fruiter, producing red fruits that persist through winter. This plant is moderately salt tolerant, has known pest problems, and is mildly resistant to damage by deer. 

Originally, there were five Foster's Holly clones. Clones 1 and 5 are no longer available. Clone 4 is a male and clones 2 and 3 are female and virtually indistinguishable. 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.

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 winter to maintain a desired size, although keep in mind that the plant flowers on new growth. Plants can suffer from the cold in USDA Zone 5 and below. 

Insects, Diseases, and Other Plant Problems: Insect problems include holly leaf miner, spittlebugs, spider mites, whitefly, and scale. Susceptible to leaf spot, leaf rot, tar spot and powdery mildew, leaf drop, leaf scorch, and chlorosis (yellowing of leaves in high pH soils).

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.