Try growing Skimmia...you ‘mite’ like it!

Skimmia

Skimmia japonica
Family: Rutaceae (Citrus family)
Genus: Skimmia
Featured species: japonica

Picture courtesy of Oregon State University Landscape Plant Database

If you were to reach for your dial-a-plant and ask for a hardy, evergreen type that thrives in acid soil in the shade…offers attractive and fragrant foliage and flowers as well as bright-red berries…has the shape to serve as an accent but also the sociability to line up in a hedge or cluster with its fellows, and is on a scale suited to the typical home landscape…you would find that Skimmia japonica meets all these criteria, and more.

This small shrub is easy to spot around Whatcom County now. S. japonica is usually about three-feet tall with a two-foot spread. Its leathery, oblong leaves are three to five-inches long and clustered at the ends of the branches, similar in form to a rhododendron. Its fresh green leaves and sparkling red berries brighten our surroundings in these last weeks of winter.

Skimmia is another of the many genera native to Asia. S. japonica is found in the forests of Japan, Taiwan, and on the island of Luzon, where it often grows as an epiphyte on old Cryptomerias. Its cousin S. laureola, distinguished by black berries and a more elongated leaf form, is indigenous to rocky forests at higher elevations in Nepal and China. Since it is a forest-dweller, no Skimmia should be planted where it will get direct sun in the spring, summer, or even fall. Unless it is in light to medium shade, Skimmia will develop an unattractive case of leaf burn. It can tolerate deep shade, although it will become leggy under conditions of very low light. Because winter sun is not much of an environmental factor in the Pacific Northwest, many gardeners here choose to plant S. japonica underneath larger deciduous shrubs or trees.

Skimmia japonica requires acid soil and regular moisture and cohabits nicely with other plants requiring similar conditions. Add plenty of organic material when you first plant it, and make sure any mulch or soil amendment you use is suitable for acid-loving plants. If the leaves of your Skimmia turn yellow, consider all the possibilities before assuming it is chlorotic and dosing it with chelated iron. First, it might be getting too much sun, which burns the leaves. Or, it might be unable to absorb adequate amounts of manganese or iron from soil that is too alkaline for its tastes.

Is your Skimmia planted close to a concrete foundation or receiving runoff from one? If the growing conditions are right, then it is likely that your S. japonica is infested with spider mites or with its own particular pest, the citrus red mite (Panonychus citri). Every Skimmia in Whatcom county, some say, hosts this brown, eight-legged critter. Look at the plant carefully. Do the leaves have brown edges and a uniformly yellow interior or do they appear stippled, without brown edges, and are there little beasties in evidence? Your Skimmia will survive the infestation, if it is in robust good health. This is a test of your tolerance for the damage wrought by the mite. Some gardeners find the almost variegated appearance of the leaves to be attractive. Give your Skimmia a blast of water from the hose or, at the most, administer insecticidal soap. Remember that the mites bothering your plant (and, presumably, you) are in turn being fatally bothered by other, predator mites, upon whom we want to look kindly. The insecticidal soap will eliminate them, too. This is yet another opportunity to contemplate that cardinal rule of Master Gardeners: right plant, right place, appropriate and regular care. If we’ve done everything right for the right plant, then it can withstand an annual mite assault. The question is, can we?

There is another consideration for those who cultivate Skimmia japonica, having to do with gender. Skimmia is dioecious: there are male plants and female plants, and both are required to set seed. Both have flowers, but only the females produce berries and then only if a male plant is very near. Many feel the beautiful red berries justify the extra effort required to plant both types. Some even advocate helping Mother Nature along by hand-pollinating the female flowers when the male flowers release their pollen. There is another solution available, however. A subspecies of S. japonica, subsp. reevesiana, is hermaphroditic. It is a shorter plant, reaching only about two feet in height, and its berries are smaller and a more subdued red. It is often labeled Skimmia reveesiana and is readily available at retail garden centers.

Whichever Skimmia you choose, you will be rewarded with an attractive, truly evergreen shrub that will shine in the late winter and hold its attractive flowers all season while it provides a green backdrop for the more exuberant plants of spring and summer. And you will have the opportunity, if you choose, to adopt an attitude of peaceful coexistence toward mites, both harmful and beneficial. They’ll fight it out among themselves.