Koehne Holly Ilex x koehneana 'San Jose'

Koehne holly, is a hybrid cross between I. aquifolium and I. latifolia. 'San Jose' is a cultivar of this cross with an erect, narrow-pyramidal, densely-branched form. The hybrid name koehneana honors Bernard Koehne (1848-1918), a German botany professor.

This large evergreen shrub or small tree typically grows to 20 to 25 feet tall with a spread of 12 to 15 feet wide. Branches are clad with glossy, spiny-margined, elliptic, evergreen, dark green leaves (2 to 3 inches long). Fragrant, but tiny, greenish-white flowers bloom in May. If pollinated by a male plant, flowers give way to berry-like red drupes (1/3 of an inch in diameter) that ripen in fall and persist into winter. Birds are attracted to the fruit.

'San Jose' grows well in medium moisture, well-drained soils in full sun to part shade. Although rather cold hardy, it does best when protected from cold winter winds and partial afternoon shade should be available to the site if grown in hot summer climates. Prune in winter if needed. This hybrid holly is a dioecious female (meaning that there are separate male and female plants and the female plants need a male pollinator nearby in order to bear fruit).

Insects, Diseases, and Other Plant Problems: Potential insect problems include holly leaf miner, spider mites, whitefly and scale. Potential disease problems include leaf spot, leaf rot, tar spot and powdery mildew. Plants are also susceptible to leaf drop, leaf scorch and chlorosis (yellowing of leaves in high pH soils).

The Clemson Cooperative Extension Home and Garden Information Center has a factsheet on common diseases and insect pests.

VIDEO created by Andy Pulte for “Landscape Plant Identification, Taxonomy and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.

More information on Ilex x koehneana.