Cultivar Close-Up: Quercus aliena 'Lutea'

Nurseryman Don Teese from Victoria, Australia wrote to the IOS last month with some interesting information about the cultivar Quercus aliena ‘Lutea’. This selection was described in 2016 by Ryan Russell and Eike Jablonski in International Oaks No. 27 (pp. 146–148), though it had been named and was in cultivation in Japan since before 1959. It is a small tree (6 × 5 m), slower growing than typical Q. aliena and distinguished by having pure yellow new leaves in spring that become glossy light green throughout the summer. According to Russell and Jablonski, the oak cultivar has been cultivated since the early 1960s at Shibamichi Nursery near Saitama, on the outskirts of Tokyo, and in some other Japanese nurseries. Akira Shibamichi, owner of the nursery, told them that the original tree, possibly over 200 years old and with a girth exceeding 4 m, is known to the local people of Kyushu Island, the most southwesterly of Japan’s main islands.

The cultivar is rare in cultivation outside Japan: it is not listed in the Cultivated Oaks of the World database, and though a herbarium specimen at the Sir Harold Hillier Gardens was taken from a specimen growing there in 1998, all of the several trees in that collection have since died. In Australia, however, this oak has been in cultivation for about a century. According to Don Teese it was extremely rare till he started grafting it. “I believe it arrived in Australia via Gembrook Nurseries—later Nobelius Nursery,” he said. “Nobelius was at the time the biggest nursery in the Southern Hemisphere, selling to Asia, Europe, South Africa, and the U.S. Carl Nobelius, founder of the nursery, visited Japan around the late 1800s and early 1900s, and brought back many plants including the first Kiwi fruits (Actinidia chinensis var. deliciosa), which were sent to New Zealand, starting that industry.”

The oak appears in the Nobelius catalogs from the 1930s as Q. mongolica ‘Aurea’, and it was also known as Q. dentata ‘Aurea’ and Q. aliena ‘Aurea’. The epithet ‘Lutea’ means “yellow” and derives from the Latin lutum, the name for a plant used to extract a yellow dye (Reseda luteola, known as dyer’s weed or dyer’s rocket).

Don found a tree in a garden near him which could have dated from the 1930s. “It was very sick, but after several years trying, a few grafts survived and then we were away,” he said. “It is difficult to graft and we have only ever had one gold seedling in many years. We have used Q. dentata as the under stock, which seems to be compatible once it takes. I suspect the almost translucent wood on young twigs just doesn’t have much chlorophyll so it grafts at a poor percent.” According to Russell and Jablonski, the main feature of the cultivar is its yellow foliage in spring, but Don points out that the leaves are also attractive in autumn, when they again turn from summer’s pale green to a rich yellow (see photo below).

All photos © Don Teese, unless specified