Japanese Camellia

Japanese camellia (Camellia japonica, Theaceae) is a slow-growing evergreen shrub from Japan and China, found wild in forests at 300 to 1,100 meters elevation. It typically reaches 10 to 15 feet tall with a dense pyramidal form. Alternate, simple, ovate to elliptic leaves (2.5 to 10 centimeters) are dark lustrous green and leathery with serrate margins. Flowers range from 6 to 13 centimeters across in forms including single, semidouble, formal double, and peony types, in colors spanning white, pink, rose, and red. Bloom occurs from early winter to spring.

Japanese camellia grows in sun to part shade (part shade preferred) on moist, acid, organic, well-drained soil (pH 5.0 to 6.5), hardy in Zones 7b to 8b. It blooms on old wood and should be pruned immediately after flowering. Over 2,000 cultivars have been bred, including 'April Remembered,' 'Kramer,' 'Marie Bracey,' and 'Nuccio.' Disease pressure is significant: 12 associations are documented, including flower and petal blight, leaf gall, Ramorum leaf and shoot blight, sooty mold, and cold injury. Pest associations include cottony camellia scale, brown soft scale, aphids, root weevils, and black citrus aphid.

Japanese camellia thrives in the Puget Sound lowlands where our naturally acidic soils (pH 5.0-6.0) and mild winters suit it well. The main risk is flower blight (Ciborinia camelliae), which disfigures blooms during wet late-winter and early-spring weather and is endemic here. Remove fallen petals to break the cycle. Cottony camellia scale is the most common pest. Sudden cold snaps below 10F can damage flower buds and foliage, particularly when preceded by warm spells. Site in morning sun with afternoon shade to protect blooms from sunscald and to reduce cold injury from radiant heat loss. Our clay soils demand raised beds or generous organic amendment for drainage. Ramorum blight (Phytophthora ramorum) is a regulated concern in this region; all Camellia species and cultivars are subject to nursery inspection protocols.

— Chris Welch, ISA Certified Arborist