A medium-sized tree with slender branches and elegant habit, bursting into leaf early; young shoots glabrous, prominently angled. Leaves diamond-shaped or obovate, tapering about equally to both ends, sometimes more abruptly towards the apex; minutely and regularly blunt-toothed, 2 to 5 in. long, 11⁄4 to 31⁄2 in. wide, dark green above, very pale beneath, glabrous on both sides; stalks 1⁄2 to 1 in. long (shorter on the leaves of long shoots). Male catkins 3⁄4 to 11⁄4 in. long; stamens eight.
Native of north and west-central China; discovered by Eugène Simon in 1862 N.E. of Peking and introduced by him at the same time by means of plants sent to the Paris Museum and to the Simon-Louis nursery at Plantières near Metz. It is one of the balsam group breaking into leaf early, and fragrant then. Its distinguishing characters are its angular young shoots devoid of down, and the variable but often very short leaf-stalk. The original tree at Plantières had a trunk white almost as a birch.
P. simonii is represented at Kew by a tree planted in 1899, measuring 48 × 23⁄4 ft (1967). It is, however, a very rare tree in this country, probably because of its susceptibility to bacterial canker.
cv. ‘Fastigiata’. – A tree of narrow habit, with ascending branches. Introduced by F. N. Meyer from N. China in 1913. A fastigiate clone cultivated in Britain came from France under the name P. simonii obtusata. This may possibly represent a different clone from the one sent by Meyer.
P. cathayana Rehd. – This species appears to be related to P. simonii, but with terete young stems and the leaves on the short shoots ovate or narrow-ovate, acuminate, rounded or broad-cuneate at the base, up to about 4 in. long. It was described by Rehder in 1931 and is said to be a native of China from W. Szechwan to Manchuria, possibly also of Korea, and to have been introduced by Wilson. A plant seen under the name P. cathayana agrees better with P. trichocarpa, but what is probably the true species grows in the Forestry Commission stool-beds at Alice Holt.