The attractive evergreen foliage and bright red fruit of this small tree make it a very popular for landscaping. Cuttings are popular additions to Christmas wreaths and decorations.
It is important to plant males as well as females if berry production is desired; the gender ratio should be 1:10, males to females. American hollies need to be protected from harsh winds. Holly plants prefer partial shade, with some full sun exposure during the day. Utilize containerized or balled and burlapped plants as bare root transplants have marginal success.
Cultivars of I. opaca should be used for landscaping, since they will have superior appearance and utility to most seedlings. There are many cultivars to choose from, but those listed below are most winter hardy.
‘Canary’ – yellow-fruited with abundant fruit production.
‘Clarendon’ – dwarf, shrubby form reaching 8′ tall and much wider. It bears glossy olive-colored leaves and orange-red berries.
‘Croonenburg’ – Bears both female and male blooms on the same plant, thus it may bear red fruit without a separate pollinator. It is a columnar, dense tree with glossy leaves that are less spiny than normal.
‘Howard’ – Nearly spineless, dark green leaves and abundant red fruit. The habit is columnar and dense.
‘Jersey Knight’ – Male form with good dark green foliage, good pollinator.
‘Jersey Princess’ – Widely considered one of the finest fruiting cultivars, holds its bright red fruit well into winter.
‘Maryland Dwarf’ – Mature height is around 3′ tall, but it may spread to 10′. The foliage is glossy and deep green.
‘Old Heavyberry’ – One of the best cultivars available, vigorous with large dark green leaves and profuse large red fruits, very good winter hardiness.
‘Steward’s Silver Crown’ – Variegated, leaves edged with cream and red fruit.
f. xanthocarpa – naturally-occuring variant includes all yellow-fruited forms.
American Holly – USDA Fact Sheet
American Holly – Missouri Botanical Garden
American Holly – UCONN Plant database