Hollies are easily recognized by their alternate leaves. The flowers are generally inconspicuous with sexes on separate plants. It is essential to have both staminate and pistillate plants in the same general vicinity to insure proper pollination. Poor fruiting on hollies is a problem many gardeners experience. This could be due to poor pollination, young immature plants, high nitrogen levels in the soil, or a late spring frost which injures flowers.
Good drainage is required, especially on the Japanese (crenata) hollies. Chinese (cornuta) and dwarf yaupon (vomitora nana) seem to tolerate wet feet much better. Plenty of organic matter, especially in sandy soils, will also be helpful. Holly beds should be well-mulched and fertilized with a complete fertilizer to remain healthy. The soil pH should be between 5.0 and 6.0.
Maintenance requirements will include pruning of the vigorous growing cultivars, and controlling leaf miner, Japanese wax scale, and redmites. Root rot diseases are a problem with several Japanese cultivars.
The following is a partial list of Hollies which grow well and are versatile in North Carolina landscapes.
Botanical Name and Common Name Landscape Remarks Ilex x altenuata 'Fosteri' Cross between 1. cassine x FOSTERI HOLLY opaca. Favorite upright, small tree form, good fruit production. Popular as foundation planting on corners of structures. Ilex aquifolilum Lustrous, dark green, spiny ENGLISH HOLLY leaf. Many cultivars available. Ilex cassine Excellent tree form, hardy DAHOON HOLLY Zone 9, red berries.Good for eastern N.C. landscapes. Ilex cornuta Hardy to Zone 7. Typically CHINESE HOLLY reaches 9-12' in height, medium to coarse texture. Favorite cultivars include: 'Burfordii' - heavy fruit crop, can get very large. 'Dwarf Burfordii' - 5-6', does not fruit as heavily as 'Burfordii'. 'Carissa' - dense, dwarf, 3-4' high. 'Rotunda' - compact, dense, spiny leaves; to 5' if not maintained. Ilex crenata Hardy to Zone 6, can reach JAPANESE HOLLY 9-12' in height, medium to fine texture (smaller leaves than cornuta). Dense, multi stem evergreen shrub. Favorite cultivars include: 'Compacta' - globose form, requires little pruning, to 6'. 'Convexa' - very hardy, dense, can grow to 9'. 'Green Luster' - dark green, lustrous foliage. 'Helleri' - low spreading, 3' height x 5' width. 'Hetzi' - more compact than 'Convexa'. 'Kingsville Green Cushion' - very low-spreading form. 'Microphylla' - hardy Zone 5 very small leaves. 'Rependens' - small, narrow leaves; maintained at 3' easily. 'Rotundifolia' - rounded form, easily reaches 8-12'. 'Stokes' - not as hardy as 'Helleri' but remains compact. Ilex decidua Deciduous large shrub (30') POSSOMHAW HOLLY with crenately-toothed leaves. Fruits bright red or orange and very showy in fall and winter. Ilex glabra Grows 6-8' tall, rounded INKBERRY form, hardy all across N.C. Slow growth rate, black berries produced, showy in fall. Ilex x 'Nellie R. Stevens' Upright, pyramidal, dense small tree form. Hybrid between 1. aquifolium x 1. cornuta. Hardy to Zone 6. Ilex opaca Grows 50-60' tall, medium to AMERICAN HOLLY coarse texture. Females fruit heavily in fall, needs 1 male for every 2-3 females; pyramidal form. Many cultivars available. Ilex 'pernyi' Pyramidal, upright habit. PERNY HOLLY 9-12' tall, hardy to Zone 6. Ilex verticullata Deciduous shrub; withstands SPARKLEBERRY wet conditions, active to swampy areas fruit very showy in fall and winter. Several cultivars available. Ilex vomitoria Hardy to Zone 7. Native to YAUPON coastal areas; tree form reaches 15-20'. Translucent berries, gray bark. Ilex vomitoria 'Nana' Low growing shrub form; very DWARF YAUPON dense, branching habit.