Japanese kerria brightens winter landscape
There are some plants in my landscape that I must admit I don't give much attention most of the year. Kerria japonica seems to vanish in the shrub border along the west side of our backyard except for a brief period in spring and during winter.
Commonly called Japanese kerria, Japanese rose and Japanese globeflower, Kerria japonica prefers a spot in the landscape with average, well-drained soil in part shade. It is adaptable, tolerating soils that are both wet and dry, and in my garden grows beautifully in full shade.
It grows 4 to 6 feet tall and is wider than it is tall, spreading by suckers to form sizable colonies. Five-petaled, bright golden-yellow flowers bring Kerria japonica out of hiding for several weeks in spring. The more sun it receives, the greater the number of flowers; but in full sun, the color of blossoms may dim.
Flower buds for the following year's flowers are set on old wood so if pruning is required, it must be done right after flowering to avoid cutting off next year's flowers. Dead branches should be pruned out whenever they are found. Old plants can be rejuvenated by cutting the entire shrub down to the ground. And, if the shrub is getting too wide for your liking, remove suckers to control its size.
After flowers fade, Kerria japonica fades into the shrub border again, its narrow, bright green leaves blending with the foliage of dogwood, dark green needles of yew and finely-cut foliage of Sorbaria sorbifolia Sem. These shrub buddies are perfectly happily to screen unwanted views into the neighbor's yard without fanfare all summer long.
And then comes fall and winter. The leaves hold on until they can't any longer, leaving naked branches behind. This is when Kerria japonica garners my attention. Thin, bright green stems create a thicket of colorful exclamation points in the shrub border. They positively glow in front of evergreens.
Utilize this shrub like I do, in shrub borders, or let it naturalize on slopes, reducing soil erosion. It would also be lovely planted with ornamental grasses or in front of a rock wall.
Good bedfellows for Kerria japonica include spring-blooming perennials with blue flowers like Pulmonaria Bertram Anderson or Virginia bluebells. Soften the golden yellow blooms with a white-flowering ground cover like sweet woodruff and white tulips or daffodils. Or, go bright by surrounding it with bleeding hearts (Dicentra spectabilis), false forget-me-not (Brunnera macrophylla) and variegated hostas.
There are several garden-worthy cultivars of Kerria japonica. Golden Guinea grows taller than the species -- 6 to 8 feet tall -- and its flowers are larger, too.
Plentiflora (also sold as Flore Pleno) also grows 6 to 8 feet tall but more upright. It flaunts double, bright yellow flowers that look like little pompons cheering on the arrival of spring.
Picta sports variegated foliage. Rich green foliage edged in white adds interest all season on shrubs growing 6 feet tall. Like most variegated plants, it is less vigorous and doesn't send out suckers as energetically as other cultivars. Be sure to watch for and remove any leaves bearing solid-colored leaves.
• Diana Stoll is a horticulturist, garden writer and speaker. She blogs at gardenwithdiana.com.