Kerria

( KEHR - ee - uh )

At-A-Glance Information

Kerria japonica (the only species in the genus) is commonly called Japanese Kerria or Japanese Rose, is a deciduous flowering shrub species that prefers full sun in cooler climates and partial shade elsewhere. It takes moderate to regular water, and has an open, graceful habit. This species is native to Japan and China, and gets to about 6 feet tall and 8 feet wide. Leaves are generally bright green, and flowers are small and yellow, mimicking tiny yellow roses. Main bloom is in spring, and sporadic blooms continue through early summertime. Take care when planting these shrubs in the landscape, as there is evidence that ingestion of plant parts is toxic for humans and animals.

Kerria japonica Varietals

The genus Kerria was named for Scottish gardener William Kerr, includes only one species and is a member of the plant family Rosaceae. The best growing zones for Kerria japonica are 2-23. To find your zone, click here: Zone Map.
'Golden Guinea'
Larger flowers than the species.
'Picta'
Yellow flowers, leaves edged in white.
'Pleniflora'
​(Bachelor's Buttons)
The most commonly grown varietal; double flowers appear in summer and fall. Vigorous growth to 8-10 feet tall and wide.

Caring for and pruning Kerria shrubs

Plant Kerria japonica shrubs in spring or fall in a spot that receives part shade to full sun (flowering will be better in partial shade). These plants aren't super picky about soil type, but perform best in well-draining fertile soil with a pH of between 4.5 and 8.5. Mulch around the base of the plant. Keep soil moist, especially during the active growing seasons in spring and summer. Once established, these shrubs are drought tolerant but do best with regular waterings. After flowering fades in spring or early summertime, prune to remove dead flower heads and remove dead or damaged wood. These plants can also be hard-pruned for rejuvenation. While these shrubs are growing, pinch branch tips infrequently to encourage a more bushy habit. Provide some cold protection, especially in cooler areas of this shrub's zone range, and apply a balanced, slow-release fertilizer in springtime to support new growth. 

Propagation

Kerria shrubs can be propagated by using cuttings. To propagate your shrub, follow the instructions below:

Propagating Kerria by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In late spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Problems and Pests

Kerria japonica shrubs are resistant to pests and disease. For information on common home garden pests and diseases, consult the following pages:
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Gallery

Kerria japonica shrubs provide great yellow color to border gardens.
Plant these shrubs close to walkways or gathering spaces where their beautiful blooms can be admired.
These shrubs look great in cottage-style gardens.

Videos

All about a great variety of Kerria japonica, 'Pleniflora'.
How to grow and care for Kerria japonica.

Resources

Kerria japonica Growing and Propagating
Kerria japonica 'Pleniflora' (Japanese Kerria)
Wikipedia: Kerria japonica
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 392, Kerria japonica
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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