*Aucuba japonica* ‘Rozannie’ in the Seattle Japanese Garden, Area E. (photo: Corinne Kennedy)

Aucuba japonica is a large evergreen shrub native to the warmer areas of Japan, and to South Korea, Taiwan, and southeast China. Grown world-wide, especially its variegated forms, it’s all too often viewed as commonplace and unremarkable. Nonetheless, it’s a tough and adaptable species with some very attractive cultivars. The Seattle Japanese Garden has many plants, including some with yellow variegation, but most are located along the east-side fence, not visible from the Garden’s main path. Fortunately, two Aucuba japonica ‘Rozannie’ shrubs were added in 2021. A compact female cultivar, it features showy, bright red berry-like fruits that develop in fall and last until the following spring. Both plants are easily seen, located just past the first fork in the main path, next to the stream.

Aucuba japonica in the wild:

In the wild, Aucuba japonica is an understory evergreen shrub or small tree, growing in warm-temperate to subtropical moist forests. It usually grows at lower elevations, along streams and wet slopes, and often in large, dense groups. In Japan, it also grows in plantation forests of Chamaecyparis (hinoki false cypress) and Cryptomeria (Japanese cedar).

Aucuba japonica is known by several common names, including Japanese aucuba and Japanese laurel. Its foliage and fruits remind us of hollies, and in growth habit it resembles rhododendrons, but it’s not related to either. Nor is it a laurel, but instead is more closely related to the dogwoods. [Until recently, it was included in that family, Cornaceae, but has been reclassified into the related silktassel family, Garryaceae.]

Growing in the wild in full or part shade, Japanese aucuba often becomes quite large, up to about 15 feet tall. Especially when growing in deep shade, it develops a divergent habit of growth, with twisting and crossing branches. Nonetheless, with their large, leathery leaves, up to 10 inches long, species plants often appear relatively dense and full. Oblong in shape and held opposite on their stems, leaves are a lustrous deep green, edged with large serrations. Many cultivars have been developed from the species, including yellow-variegated forms as well as some with all-green foliage.

Young leaves and flowers of *Aucuba japonica*. (photo: Andy Morffew, Wikimedia Commons)

Japanese aucuba is dioecious—that is, each individual shrub is male or female, forming only male or female flowers. Very small, star-shaped, and consisting of four or five maroon petals, they open in early spring, just before the new leaves. Female flowers are held in short clusters, but the slightly larger male flowers appear in panicles (pyramidal, loosely branched flower clusters). In addition, the male flowers have four small yellow stamens (the pollen-producing parts of a male flower) arranged in a circle around the flower’s center, while the female flowers have one central green pistil (the parts of a female flower from which seed is produced). Though they’re not considered showy, both male and female flowers are quite pretty when viewed up close. To ensure that female plants will set fruit, one male plant is needed to pollinize several females located nearby. [According to some experts, though, the cultivar ‘Rozannie’ is self-fruitful. See below.]

The large, oblong, berry-like fruits are green at first, maturing to a beautiful, glossy bright red. [Botanically, they are classified as drupes, simple fleshy fruits that usually contain a single seed.] Fortunately, they are unattractive to wildlife, including birds and deer, so most will remain on the shrub throughout the winter, with female plants remaining showy for many months.

Aucuba japonica grows best in shade or part shade, in moist, well-drained, humus-rich soil, and is reliably hardy to USDA Zone 7 (minimum temperature 0 degrees Fahrenheit). However, it is a remarkably adaptable plant, and will tolerate sandy or clay soils, ocean breezes, urban pollution, and even deep shade. In Japan it is commonly grown in full sun, its large leaves protected from the sun’s harshness by that country’s very rainy summers. Here in the Pacific Northwest, though, it grows best in part shade, shade, or even deep shade. It’s considered drought tolerant under those conditions, but during our dry summers will remain healthiest and most attractive with occasional summer irrigation. Because of its large leaf surfaces, it should not be planted in exposed sites subject to harsh winter winds.

Aucuba japonica as an ornamental, in Japan and worldwide:

For blog readers interested in the history of cultivated plants, the website Tokyo Naturalist has a fascinating summary of the history of Japanese aucuba—in Japan and worldwide. The website “is run by a group of citizen scientists, science educators, horticultural professionals, university students, and amateur naturalists identifying, documenting, and writing about the diverse plant, animal, and insect life found in one of the world's largest metropolitan areas.” Here’s their summary—but please feel free to go on to read about Aucuba japonica ‘Rozannie,’ skipping this section:

Aucuba japonica is a familiar sight in parks, gardens, and cities around the world where it has built a reputation for bringing green to metropolitan areas for over 300 years. In fact, this plant is so green that, in Japanese, it’s blue: the name アオキ (Aoki) meaning “evergreen shrub” also has a literal meaning of “blue tree.”

This, however, is not due to an optical illusion or special plant properties, but rather the result of a nuance in the history of the Japanese language. Ancient Japanese included four words for colors: red, blue, black, and white, which some suggest indicated degrees of brightness, darkness, and tone. In this system, shades of green (緑, midori), were incorporated under the word 青 (ao, blue). Though Japanese today features a vast variety of color terms, using 青 (ao, blue) for things typically seen as 緑 (midori, green) is not totally uncommon, especially in relation to fresh vegetation. As such, it is said that Aucuba japonica, whose leaves and new branches appear noticeably deep green year-round, garnered the name アオキ (Aoki).

… The enduring deep green of Aucuba japonica played a prominent role in its eventual worldwide spread as an ornamental plant. During the Edo period (1603-1868) the population of Tokyo (then called Edo) rapidly expanded, completing the city’s transformation from a small village into one of the world’s largest population centers, with over one million people residing in the city by the mid-1700s. As the city expanded, access to nature and green space became more limited, heightening the demand for urban-tolerant trees and shrubs that remained green all year. The evergreen Aucuba japonica met this need, and was broadly planted in private gardens and parks throughout the city.

As it happened, Aucuba japonica also found itself in the middle of another fad during this time: the cultivation of plants with variegated leaves, or leaves that feature differently-colored patterns or edges. Also known to some as the “Gold Dust Plant,” some cultivars of Aucuba japonica feature golden spots on their leaves, making it an even more attractive option for a garden shrub. This, in addition with its ability to grow well in the shade and its tolerance of air pollution and poor soil conditions, made it a staple ornamental plant species in urban centers around the world, where it continues to be cultivated.

Foliage of a variegated Japanese aucuba in the Seattle Japanese Garden. (photo: Corinne Kennedy)

Fortunately, Aucuba japonica and its cultivars have not become invasive when grown in regions of the world where it is not native.

Aucuba japonica ‘Rozannie’

'Rozannie' Japanese aucuba is a compact female form which has large (about 5 inches long by 2 ¼ inches wide), lustrous, dark green leaves with a few coarse serrations near their tips. Glossy bright red berry-like fruits form in November and remain on the plant for several months. Whether it is truly self-fruiting (setting fruit without a male plant nearby) is unclear. Most authorities assert that it is (although with heavier fruiting in the presence of a male plant), but some report that it has behaved in their gardens like a typical female aucuba, requiring a male pollinizer to set fruit. One of the two female plants in the Seattle Japanese Garden is thriving, and last fall’s fruit remained showy when I photographed it this past April. But it looks like it may not develop fruit this fall. So we shall see…

Cold hardy to USDA Zone 6 (minimum temperature -10 degrees Fahrenheit), ‘Rozannie’ is a very tough, attractive, and useful shrub. It grows best in part to full shade and in rich, well-drained soil with occasional summer water. Very sunny, hot exposures will result in unattractive foliage—paler green, even yellowish, and less lustrous. But like the species, ‘Rozannie’ is tolerant of a wide range of soils, and once established will thrive in dry shade. According to greatplantpicks.org, “it’s a great competitor with the conifers of the Pacific Northwest!”

With its compact habit, ‘Rozannie’ grows to 3-4 feet tall and wide in 10 years. Its mature size will be about 6 feet tall and wide, but it’s easily kept lower with skillful pruning. It’s an excellent choice for a container, low hedge, foundation plant, or woodland garden—and an attractive addition to our Seattle Japanese Garden. I confess that until doing research for this article, I didn’t sufficiently appreciate Aucuba japonica as a species or its cultivar ‘Rozannie.’ Now, as climate change is stressing shrubs in my garden that have previously done well, I’ve decided to plant ‘Rozannie’ the next time one of them dies and gives me the opportunity to add a shrub that’s likely to thrive.

Corinne Kennedy is a Garden Guide, a frequent contributor to the Seattle Japanese Garden blog, and a retired garden designer.

The Showy, Bright Red Fruits of Aucuba japonica ‘Rozannie’ Remain on the Plant from Fall until the Following Spring