Kerria

( KEHR - ee - uh )

At-A-Glance Information

This genus of flowering shrubs is commonly called Japanese Kerria, Japanese Rose, Easter Rose, Bachelor's Button, or Yellow Rose of Texas. It forms a deciduous flowering shrub that prefers full sun in cooler climates and partial shade elsewhere. These shrubs can take moderate to regular water, and have 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 mildly toxic for humans and animals.

Kerria Japonica Varietals

The genus Kerria was named for Scottish gardener William Kerr and includes only one species (Kerria japonica). It is a member of the plant family Rosaceae, and is related to Rubus, Rose, Spiraea, and Malus. The best growing zones for these shrubs are USDA hardiness zones 4-9 or Sunset growing zones 2-23. To find your zone, click here: Zone Map. Note that Kerria japonica is considered invasive in the Eastern and Southeastern United States due to its aggressive spreading via suckers.

'Golden Guinea'
Larger flowers than the species. To 5-6 feet tall with heavily veined foliage.

'Kin Kan' ('Aureovittata')
Cultivated for its distinct stems that turn bright yellow with thin green striping in wintertime.

'Picta' ('Variegata')
Yellow flowers and leaves edged in white on a 4 foot tall shrub.

'Pleniflora'
(Bachelor's Buttons)
Double flowers appear in summer and fall. To 6-8 feet tall and wide.

'Simplex'
The standard form of the species. With golden flowers and bright green arching stems.

'Shannon'
Vigorous to 6 feet tall, with extra-large yellow flowers that bloom early.

Caring for Kerria

Take care when planting these shrubs in the landscape, as there is evidence that ingestion of plant parts is mildly toxic for humans and animals. Plant Kerria in spring or fall in a space in the landscape that receives full sun to partial shade. These shrubs will actually flower more if they have some good shade, especially during the warmest parts of the afternoon. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 4.5 and 8.5 (acidic to slightly alkaline). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered to be drought-tolerant, but will perform well in consistently damp soils. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. As these shrubs are establishing themselves in the garden, they can be pinched back to encourage a bushier form. These shrubs bloom exclusively on old wood, so the best time to prune them is right after flowering ends around late spring or early summertime. Older shrubs that have become leggy or have a 'bald spot' in the center from their drooping branches can be hard-pruned for rejuvenation. If variegated forms revert back to fully green foliage, simply cut those branches back to the base. These shrubs are known to sucker and can cause an issue if they spread too far in the landscape; make sure to remove suckers when they are identified.

Propagation

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

Propagating Kerria by Cutting

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. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
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.
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.
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 shrubs are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. They are resistant to pests and disease. For information on common home garden pests and diseases, consult the following pages:

Pests & Pest Management

Plant Issues