Kerria japonica ‘Pleniflora’        Family: Rosaceae
(KERR-ree-ah  ja-PON-ih-ka)

Common name: Japanese kerria; Japanese yellow rose
Zone: 4 – 9
Height: 5 – 8 ft (1.5 – 2.4 m)   Spread: 4 – 6 ft (1.2 – 1.8 m)
Aspect: partial shade; full shade
Soil: average; humus-rich; well-draning
Water: moderate
Description: Deciduous shrub with multiple bright green, upright and arching stems adorned with small, narrow, double-toothed ovate-lanceolate bright green leaves arranged alternately along the branches. Pompoms of double, golden yellow flowers appear in early spring, lasting for 2 to 3 weeks.


Special Notes: Native to Japan and China, this plant cultivar was introduced to Great Britain in 1805 by Scottish plant collector, William Kerr. Tolerant of all soil types except clay and those with poor drainage. Valued for its reliability in producing masses of blossoms in shady conditions. It is also tolerant of sunnier locations when provided with adequate moisture but the flowers will fade quickly in direct sun.

Deer and rabbit resistant. No pest and disease problems with the exception of possibility of kerria twig and leaf blight, a fungal disease caused by Blumeriella kerriae. This causes leaf spots and stem lesions which, if severe enough, may result in defoliation. Control spread by severely pruning out diseased stems, raking up leaves and disposing them. Do not wet leaves or stems of infected plants; water using soaker hoses.


In our Zone 7a garden: We have two clumps of this plant in our garden; one gets a little more sun than the other, resulting a slightly less floral show in spring. We have found this species to be a fairly fast spreader so dividing every 3 or 4 years is advised unless you have allowed the plant adequate room in the bed. Alternately, you can remove some of the suckering growth annually in late winter.

Other than controlling this plant’s growth habit, we have experienced no other problems, disease or pest.

 

Posted on February 20, 2023