Common Name: Japanese holly
Type: Broadleaf evergreen
Family: Aquifoliaceae
Zone: 5 to 8
Height: 3.00 to 6.00 feet
Spread: 3.00 to 6.00 feet
Bloom Time: May
Bloom Description: White
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Suggested Use: Hedge
Flower: Insignificant
Leaf: Evergreen
Other: Winter Interest
Tolerate: Clay Soil, Air Pollution
Culture
Easily grown in average, medium moisture well-drained soils in full sun to part shade. Tolerant of a wide variety of soils ranging from moist to dry and from sand to clay. Prefers light, moist, acidic soils with good drainage. Established plants have some tolerance for drought. Plants may struggle with the heat and humidity of summers in the deep South in USDA Zones 8-9. Plants are dioecious (male and female flowers on separate plants), so both male and female plants must be present in order for the female plant to be pollinated and produce fruit.
‘Hetzii’ is a female cultivar which will need a male pollinator in order to produce fruit.
Noteworthy Characteristics
Ilex crenata, commonly known as Japanese holly or box-leaved holly, is a dense, multi-branched, evergreen shrub with a rounded form that typically matures to 5-10’ tall and as wide. It is native to forests, thickets and mountain slopes in Japan, Korea, China and eastern Russia (Sakhalin). It is noted for its ovate to elliptic, crenate to serrulate, glossy, spineless, evergreen, deep green leaves (to 1 1/4" long) which are attractive all year, 4 petaled white flowers which bloom in 3-7 flowered cymes in late spring (May-June), and black rounded somewhat inconspicuous fruits (drupes to 1/4” diameter) which mature in fall on pollinated female plants.
Genus name comes from the Latin name Quercus ilex for holm oak in reference to the foliage similarities (holm oak and many of the shrubs in the genus Ilex have evergreen leaves).
Specific epithet is in obvious reference to the crenate margins of the leaves.
'Hetzii' is a shrubby cultivar that grows in a rounded mound to 3-6’ (less frequently to 8’) tall. Pollinated flowers give way to berry like drupes that ripen to black and appear somewhat inconspicuous. ‘Hetzii’ is sometimes described in nursery literature as a larger form of I. crenata ‘Convexa’. Japanese holly foliage in general resembles that of boxwoods, except inter alia boxwoods have opposite leaves and no serration.
Problems
No serious insect or disease problems. Spider mites can be troublesome. Nematodes are a problem in the South.
Uses
Mass or group. Hedge. Borders. Incorporate into a foundation planting.