Ilex Crenata, Japanese Holly Tree, Shrub, and Vine Identification Fact Sheet

This is the tree, shrub, and vine identification project fact sheet for Ilex crenata, Japanese Holly. Japanese holly is more known for its use as an evergreen ornamental hedge and does not have showy fruit. This fact sheet may not be copied in part or in whole and submitted as one's own project, but may be cited as a source of facts during one's own research. See tree, shrub, and vine identification project main page for links to other plants, and evergreen shrub slideshow for pictures.

Plant Botanical Name: Ilex Crenata

Common Name: Japanese Holly

Family Name: Aquifoliaceae

Plant is Native to What Country: Japan

Plant Height at Maturity: 6-10 feet high, 10 feet wide. Helleri is a dwarf form only reaching 4 feet in height.

Plant Habit and Form: Evergreen shrubs of fine to medium texture, compact and upright yet spreading in habit. Branches spreading, rigid.

Foliage: Dark green serrated leaves arranged alternately on stems. Evergreen leaves 1-2 inches long remain shiny through winter and are widest in middle.

Bark: Smooth bark, gray to green-gray but can be brownish. Usually concealed by foliage.

Flower: Flowers dioecious, Male flowers small, dull white in clusters of 3-5. Male and female flowers bloom in May-June. Flowers are inconspicuous. Variety Helleri does not flower or fruit often.

Fruit/Seed: Black fruits, 0.25 inch round borne on female plants in fall and remaining into the spring. Fruit is hidden within the foliage and inconspicuous.

Growing Requirements: Hardy to zone 6, grows in warmer areas of zone 5 (-13 degrees F) Prefers moist well drained slightly acidic soils. Grows in full sun to part shade and is tolerant of urban areas. Withstands heavy pruning but needs protection from winter winds.

Problems and Drawbacks: Iron chlorosis occurs on soils of high pH. Spider mite is a problem especially in hot dry areas. Not reliablely hardy in Zone 5, susceptible to winter burn and winter kill in colder areas.

Special Uses: Tolerates frequent shearing and is used in formal gardens. Used in borders, hedges, foundation plantings, mass plantings, and is valued for its evergreen foliage.

ID Tips/Remarks: Dense rigid branching. Alternate serrated leaves different than the smooth alternate leaves of Buxus species.

Bibliography: http://www.hort.uconn.edu/plants/i/ilecre/ilecre1.html, http://plants.usda.gov/java/charProfile?symbol=ILCR2