Ilex crenata

Japanese holly is a handsome, evergreen shrub or small tree in the Aquifoliaceae family. The shrub is dense, multi-stemmed, rigid and compact with a rounded habit. It may grow 5 to 10 feet tall and 5 to 8 feet wide. Many cultivars of this plant are even more compact and only grow 3 to 4 feet tall. The plant tolerates severe pruning and you will find this plant often used to make topiaries. The leaves are small, alternate, glossy deep green with crenate to serrulate margins. Clusters of small white flowers bloom in the spring. These plants are dioecious, meaning that a separate male and female plant must be present for the female to be pollinated and produce fruit. If the female plant produces fruits, they are small, black, round drupes that ripen in the fall.

This holly is a native of Japan and east Asia and can be found in thickets, woods, and wet places in lowlands and mountains all over Japan.

The genus name, Ilex, comes from the Latin, Quercus ilex, for holm oak, and refers to the similarity of the leaves. The specific epithet, crenata, refers to the crenate margins or shallow teeth on the edges of the leaves.

Plant in the full sun to partial shade in acidic well-drained soil, although it tolerates a wide range of soil types, from moist to dry, including clay. The shrub can be pruned to manage its size so it works well in small spaces. It tolerates drought, shade, air pollution, poor soils, and clay soils and is easy to transplant. It does have a slow growth rate and it may not thrive in areas with high heat and humidity such as the southern United States or in USDA zones 8 and 9. It is also best to plant this shrub in protected areas to prevent damage from winter's cold winds.

The Japanese holly is pollinated by bees and is not self-fertile. Its leaves resemble boxwood, but the Japanese holly is hardier and more disease resistant. 

There are many cultivars available and used in landscaping; the parent species is rarely seen. It is abundantly planted as an ornamental in North Carolina.  It may be used as a border, foundation planting, hedge, small groups, or mass plantings.

Seasons of Interest:

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

Quick ID Hints:

• dense, multi-stemmed, rigid, and compact shrub or small tree with a rounded habit
• small, alternate, glossy deep green leaves with crenate to serrulate margins
• undersides of the leaves as translucent glands or black dots
• clusters of small 4-petaled white flowers with greenish centers that bloom in the spring
• small, black, round drupes that ripen in the fall.

Insects, Diseases, and Other Plant Problems: The Japanese holly has no serious insect pests or diseases. Spider mites and nematodes are occasional pests.  Aphids, scales, holly leaf miners, and holly leaf blight may also be seen. Alkaline soils will cause the leaves to yellow.

VIDEO created by Ryan Contreras for “Landscape Plant Materials I:  Deciduous Hardwoods and Conifers or Landscape Plant Materials II:  Spring Flowering Trees and Shrubs” a plant identification course offered by the Department of Horticulture at Oregon State University