Euonymus tonkinensis - Spindle

The Tonkin spindle tree, Euonymus tonkinensis, is a rare Asian species in cultivation. This bush produces beautiful ivory-white fruits in late summer, containing decorative orange-red seeds. Its dark green, evergreen leaves are leathery and glossy, providing an attractive backdrop for other plants or winter flowering. It prefers moist soil that doesn't dry out too much, and a sheltered location protected from cold winds, in partial shade or non-burning sun.

The Tonkin spindle tree belongs to the Celastraceae family, which includes spindle trees, as well as the powerful lianas of the genus Celastrus.  As its name suggests, it comes from Southeast Asia: Tonkin was the former name given to the northern regions of present-day Vietnam. This bush, generally not exceeding 2 metres (6 feet 7 inches) in height and width, grows in woods, forests, and scrub areas. Although described in the early 20th century, it is still very rare in cultivation. Botanists consider it closely related to another more common spindle tree species: the Japanese spindle tree (Euonymus japonicus). Like the latter, the Tonkin spindle tree has shiny, dark green, leathery, evergreen leaves with coarsely toothed margins and well-marked veins. The round stems are also dark green, which adds to the appeal of this spindle tree even in the middle of winter. In spring, the bush produces discreet clusters of green flowers measuring 5 mm (0.2 in). If the climate suits it, it is, however, the fruits that will catch the eye a few months later, from late summer to winter if the birds are not too hungry: ribbed and ivory-white, they open at maturity to reveal seeds of a bright orange-red colour. The effect is sumptuous and warms up the garden in winter!

The Tonkin spindle tree will be comfortable in partial shade or exposed to light sun. Given its origins, and even though not much is known about it, it seems wiser not to expose it to very cold climates (with temperatures below -10°C (14 °F) for several days, at least during its first years. Protect it from cold and drying winds like all evergreen spindle trees. This rare bush will make a beautiful specimen in a collectors garden, and it can also provide a lovely evergreen backdrop to showcase winter blooms such as the paper bush (Edgeworthia chrysantha), the winter sweet, white forsythia (Abeliophyllum distichum), as well as hellebores (Oriental hybrid hellebores, Helleborus sternii, Helleborus foetidus).