Mystery Yellow Flowers

These mystery yellow double flowers finally get an id. (Photo by Charlotte Ekker Wiggins)

Mystery Yellow Flowers

I forget what year this plant was given to me. It was touted as a vine that blooms in spring and then again later mid-summer, easily climbing over trellises. I don’t recall if this was supposed to grow in sun or shade so I have it growing in both conditions. The yellow reminds me of an egg yolk color, deeper than the yellow in this yellow rose handmade quilt.

I was fine not knowing what this plant was until I gave several starts to my gardening buddy Tom.

“Have you figured out what the yellow flowers are” became his substitute for “good morning” some days.

Checking my gardening books and guides, I couldn’t find anything remotely like them and the search was on.

This year, I took several photos and took them to a friend who works at a local gardening center.

Japanese rose, she said. Actually she said Kerria japonica but Tom said “give me the simple version.”

These rose-family shrubs are originally from China and Japan. They bear pretty yellow double flowers in spring and then again mid to late summer.

Japanese rose's bark and branches are also interesting. The main branches on the double flowering type arch gracefully to a height of 8-10 feet. Smaller branches radiate off the main ones in all directions so these bushes require little pruning. The bark is a pleasing kelly green to greenish-yellow, to boot -- a color retained throughout the winter. 

Grow the bush in partial shade. It is one of the most shade-tolerant of the deciduous flowering shrubs (in terms of shade not stunting flower production. The plants will also do fine in sun, but sun causes the color of the flowers to quickly fade.

Japanese rose is not overly fussy about soil. It will tolerate poor soils but may perform better in soils enriched with humus. The ground should be kept evenly moist around Kerria japonica, which prefers a well-drained soil.

Its shade tolerance gives you the option of having a deciduous flowering shrub in shady garden areas. The attractive branches also provide visual winter interest.

Choose a background against which the branch color can be displayed to optimal effect; for example, Japanese rose's kelly green stems pop against a grey cedar wood background.

Japanese Rose Care

The plant blooms on old wood in early-to-mid spring; prune just after its spring flowering is over. A second flowering later in the growing season is not unusual, but it is too late to prune at that point. Prune out dead branches as you find them.

Old plants in need of rejuvenation pruning may be cut down to ground level. Japanese rose spreads by suckering; remove suckers as they occur if you wish to control its spread. In fact, the main problem with this plant is that it spreads vigorously; stay ahead of it with regular sucker removal. 

A Japanese Rose By Any Other Name

Besides "Japanese Rose," other common names for Kerria japonica pick up on the fact that it is a member of the rose family. The common name "Easter Rose" comes from its early blooming period during Easter, in some regions. The flowers' color accounts for the common name, "Yellow Rose of Texas.”

Who Is The Plant Named After

The genus name, Kerria comes from William Kerr, who brought the plant from the Far East to the West. Kerr was one of the great 19th-century collectors responsible for importing some of the plants indigenous to China. According to the University of Arkansas Extension, Kerr also brought to North America heavenly bamboo and tree peonies.

The leaves of Japanese rose are truly a bright kelly green. (Photo by Charlotte Ekker Wiggins)

Instead of planting these as growing trellis vines, they will work nicely as specimen plants in an informal garden where their naturally sprawling branches can grow freely. I will be moving some of these just to that kind of spot in my garden!

Charlotte