Plant of the Month

Plant of the Month: July 2022

Chinese Toon Tree

Toona sinensis (A. Juss.) M. Roem.

= Cedrela sinensis A. Juss.

MELACEÆ; Mahogany Family

My book Trees of Seattle, 2nd. edition (2006), cites seven specimens of this extremely rare tree. Now, only three are known to me other than small little young ones. This article updates the matter, and supplies photos. The International Dendrology Society Yearbook for 2021, will feature this species, and supply far more detail. But I can write adequately about Seattle's population.

As for Seattle's trees, I do not know why the Meadowbrook Edible Arboretum tree died to the ground, nor if it ever resprouted or was replaced. Also, I do not know why the two street-trees cited on 20th Ave NE, disappeared.

Washington Park Arboretum therefore has the only mature Chinese Toon trees I know in Seattle. And one of the three Washington Park Arboretum conifer meadow trees died. The conifer meadow trees had been acquired as seeds in 1986, and were planted in 1993 at the northwest corner. Far south and east of conifer meadow, a 1957 accession suffers in the shade near the Boxwood collection in grid 5-1E. The 1957 tree is crowded by firs, madrona, maple, and smoke tree. Due to competition and insufficient light and water, it is a paltry 31.5 feet tall, its trunk only 1 foot 8.5 inches circumference. The conifer meadow blooming specimen, getting full sun and regular irrigation, is 32 feet tall, its non-blooming partner 40 feet tall, its trunk 3 feet 5.25 inches circumference. It is sending suckers up over 30 feet from its trunk.

The species ranges from Pakistan across Asia to Malaysia. The name Toona is an Indian vernacular, first used as a scientific name in 1803. English names include Chinese Cedar, Chinese Mahogany, Chinese Incense Tree, Chop Suey tree, Beef-and-Onion Plant, and Stir-fry Tree.

The species became known to Western science in 1743 thanks to the Jesuit Pierre d'Incarville (1706 - 1757); it was introduced to France in 1861 by G.E. Simon. It was in the North American nursery trade by 1884 if not earlier. It remains uncommon today, if not rare. To most people, the tree's main value is if kept shrubby by much pruning, so one can consume its young foliage as a vegetable, or admire its showy spring foliage coloration.

Toon tends to be a gaunt tree that can root sucker rampantly. Its mature bark is shaggy. Leaves are onion-odored, compound, to 28 (47) inches long, of 10 - 32 (40) leaflets, toothed or untoothed, hairy or not. The young leaves are esteemed as a vegetable in China. The tree also has medicinal activity.

Its young leaves start vividly pink or rose, then ivory (at least in maritime climates), turning green all summer. Fall color can be clear lemon yellow, but is commonly washed-out yellow of no beauty. Flowers tiny, in large pendulous sprays to 3 feet long, sweetly fragrant, white (or slightly lavender-pink), in June or July, attractive to bees. Fruit a 1 inch long woody capsule opening to bell shape in late fall to release winged seeds.

Record sizes. Since the tree grows rapidly, these are not very helpful without planting dates.

to 130 feet tall x 15 feet trunk circumference (in the wild)

88 feet tall x 7 feet trunk circumference (Hergest Croft, Herefordshire, England 1985)

66 feet tall x 8 feet 3 inches trunk circumference (Wakehurst Place, Sussex, England 1973)

67 feet tall x 7 feet 7 inches trunk circumference (Germantown, PA 1980)

46 feet tall x 5 feet 4 inches trunk circumference (Hartford, CT 1987)

Toona sinensis 'Flamingo'

Raised in Australia <1930. Imported to New Zealand that year, by nurseryman Hayward Wright of Avondale. Introduced to commerce in the 1950s. Named 'Flamingo' in 1981. Cultivated in the Northern Hemisphere since 1982 if not earlier. New growth especially showy pink, fading to creamy, then green.

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