Culture
Grow in average, medium moisture, well-drained soils in part shade. Tolerates full shade. Flowers pale in too much sun. Prefers loamy soils that are moderately fertile. Avoid heavy clay soils. Blooms on previous year’s wood, so prune in spring after flowering. Suckering habit can be a problem, and unwanted suckers should be promptly removed. If necessary, plants may be renovated by cutting stems to the ground.
Noteworthy Characteristics
Kerria japonica, commonly called Japanese kerria or Japanese rose, is a tough-but-graceful, spring-flowering, deciduous shrub that is native to certain mountainous areas of China and Japan. It typically grows to 3-6’ tall and to 6-8’ wide on slender, arching, yellowish-green stems that remain an attractive green in winter. Single, five-petaled, rose-like, yellow flowers (to 1 1/2” diameter) bloom somewhat profusely in spring. Double-toothed, narrow, ovate-lanceolate, bright green leaves (to 4” long) turn yellow in fall.
Genus name honors William Kerr (d. 1814), Kew gardener and collector, who collected in China, Java and the Philippines.
Specific epithet means of Japan.
Plants in the genus Kerria are sometimes also commonly called Easter rose because the flowers typically bloom around Easter time and resemble roses.
‘Pleniflora’ is a very popular double-flowered cultivar that features rounded, pom-pom-like, yellow flowers (to 2” diameter). It typically grows taller (to 8-10’) and more upright than the species. Cultivar name means full flowered. Synonymous with K. japonica ‘Flore Pleno’.
Problems
No serious insect or disease problems. Susceptible to leaf spots, cankers, blights and root rot.
Uses
An attractive flowering shrub for shady areas of woodland gardens or shrub borders. Specimen, group or mass. Informal hedge or screen. Incorporate into foundation plantings. Also effective in wild gardens or naturalized areas where plants may be allowed to sucker and spread.