Types of Japanese Holly
Popular as a substitute for boxwood hedges, the Japanese holly (Ilex crenata) is a broadleaf evergreen shrub that is highly variable, sometimes growing only 2 feet tall while other plants reach 15 feet. It is native to Korea, Japan and the Russian island of Sakhalin. The small berry fruits that form on female plants are black, although white- or yellow-fruiting varieties exist.
Japanese holly plants are gendered, producing either all female or all male flowers, a condition botanists call dioecious. The male plants only produce flowers that shed pollen and will never set fruit. These non-fruiting male selections are often preferred for use as hedge plants. Male varieties include Bruns, Beehive, Glass, Hoogendorn, Howard, Kingsville, Lemon Gem, Rotundifolia, Stokes and Variegata. Typically, literature on non-fruiting plants will specifically list if the Japanese holly selection is a male clone. Infrequently, a female-flowering selection will fail to produce fruit, mainly because of its slow maturation, diminished production of flowers, or lack of a male-flowering plant nearby.
Female-flowering Japanese holly plants that have been pollinated by bees carrying pollen from male plants will yield small black berries in summer and fall. This holly species is not grown for the beauty of its berries, and some people who like tidy-looking shrubs may find the berries distracting in the landscape display. Nonetheless, these fruits are a food source for wildlife. If you wish to have fruits on your plants, ensure you select these black-fruiting selections, including Convexa, Dwarf Pagoda, Green Luster, Golden Gem, Hetzii, Mariesii, Sky Pencil, Snowflake/Shiro-Fukurin, Soft Touch and Piccolo.
White or Yellow-Fruiting Plants
A rarity among female-flowering Japanese hollies is the mutation that leads to light-colored berries, not the usual black. White or yellow fruits contrast the foliage and are much more ornamental in a garden setting. Ivory Tower bears creamy white fruits, and is one of the few that is commonly available in nurseries.
- "Dirr's Hardy Trees and Shrubs"; Michael A. Dirr; 1997
- "A-Z Encyclopedia of Garden Plants"; Editors Christopher Brickell and H. Marc Cathey; 2004
- The Arnold Arboretum: Ilex crenata and its Varieties