Monday, October 18, 2010

Emmenopterys henryi

The lone species of the genus Emmenopterys is a very strikingly beautiful, tropical looking but hardy large tree native to western and central China ( also Burma & Thailand ). It is so rare it doesn't even have an English name.
Typically reaching around 80 feet it can after a century or so exceed 100 feet.
Some records include: 10 years - 30 x 20 feet ( I still suspect it can grow faster ); largest on record - 150 x 80 feet with a trunk diameter of 5 feet. This spectacular tree is also highly endangered with extinction. This tree has extremely high potential as an ornamental lawn shade tree and should be widely planted. It is actually a once upon a time native to North America, fossils between 44 and 49 million years old have been found in Oregon and Washington State. Neither bothered by pests or disease, this tree may live as long as 1000 years and therefore be among the longest lived of all deciduous hardwood trees. It is also one of the worlds rarest trees. By 2006 only 4 trees are known to have flowered in Europe, one of which flowers every 20 to 25 years.
The first tree to flower in the U.S. was in the collection of Dr. Allen Hirsh of Silver Spring, MD in 1994 and originating from seed germinated at Arnold Arboretum near Boston, MA in 1979
The deciduous, oppositely arranged, leathery, smooth edged, ovate leaves are up to 9 x 5 or rarely 16 x 6.7 inches in size.
The foliage is red-bronze at first later turning glossy deep green above and downy white beneath.
The extremely fragrant pure white bell shaped flowers up to an inch in length are borne in terminal panicles up to 8 x 10 inches in June. The flowers are surrounded by white bracts and the clusters resemble that of Schizophragma in appearance. The bracts do not fall off after flowering and they turn pink, red and then purple. It is among the worlds most fragrant trees and also among the most beautiful.
The flowers are followed winged seed capsules.
Though variable, it usually sets seed every 2 to 4 years.
The branches are grayish to purple and the smooth beige bark becomes rough and dark gray on older trees.
Hardy zones 6 to 9 ( tolerating at least - 13 F - I suspect this may be revised to zone 5 with further testing ) and prefers full sun on a deep moist, well drained soil. Clay tolerant. Reasonably large trees close to 50 feet do exist in Cardiff, Wales & Cornwall, England however this tree prefers hot humid summers and grows much larger and faster in the eastern U.S. which more closely resembles its natural habitat in China. North of zone 7 very young trees should be protected from cold drying winter winds.
Reproduction is from mist propagation softwood cuttings taken late spring to early summer or also seed ( very easy ) if available.

* photos taken on October 17 2010 @ U.S. National Arboretum, D.C.




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