The color yellow seems to own spring. Daffodils, forsythia, winter jasmine and Carolina jasmine are all in bloom. There is a spot of dark gold (“school bus yellow”) appearing in the woodlands. Kerria japonica (KARE-ee-ah jah-PON-ih-kah), known as Japanese Rose, has clusters of deep yellow blooms against bright green stems. Flowers appear before leaves. Kerrias are tolerant of heavy shade and inhospitable soils. They are unappetizing to deer. Flower color is paler in deep shade. Flowering is best in partial shade.
Japanese Rose has an arching habit similar to Forsythia. The shrub may reach heights of six feet or more, with an equal spread. It spreads by suckering and may grow into a hedge when left alone. To prevent spread, remove all suckers as soon as they appear. If desired, the plant can be pruned down to the ground to reduce its height. Any pruning should be done immediately after bloom season since most blooms occur on prior year’s wood. Any later pruning will reduce flowers for the following season. Stems branch in their second year of growth.
The narrow leaves turn yellow before they drop in autumn. Stems remain green throughout the winter. They have a zigzag growth habit similar to Cercis (Redbud). The cultivar ‘Pleniflora’ (sometimes listed on tags as ‘Plena’) has double flowers and is worth seeking. Its growth habit is a little more upright than ‘Golden Guinea’ which has an attractive single flower. ‘Picta’ has variegated foliage and stays smaller than the non-variegated types but is prone to reversion. If any non-variegated stems appear, prune them out immediately.
Kerrias are easily propagated from softwood stem cuttings or by removing and replanting suckers. If you have a steep bank in your woodlands (ditch or gully), use fast-growing Kerria to reduce erosion and turn an eyesore into a feature.
Yellow Kerria pompoms glow against arching green stems. This photo was taken in deep shade at Hatcher Garden and Woodland Preserve, Spartanburg SC.
Wary turtles watch as I photograph the nearby Kerria japonica.