Ulmus pumila var. arborea

Ulmus pumila cultivar
'Pinnato-ramosa', Royal Botanic Garden Edinburgh, planted 1902
Cultivar	'Pinnato-ramosa'
Origin	Germany

The Siberian elm cultivar Ulmus pumila 'Pinnato-ramosa' was raised by Georg Dieck at the National Arboretum, Zöschen, Germany, from seed collected for him circa 1890 in the Ili valley, Turkestan (then a region of Russia, now part of Kazakhstan) by the lawyer and amateur naturalist Vladislav E. Niedzwiecki while in exile there.

Originally named U. pinnato-ramosa by Dieck at Zöschen. In 1908 Litvinov treated the tree as a variety of Siberian elm, U. pumila var. arborea but this taxon was ultimately rejected by Green, who sank the tree as a cultivar: "in modern terms, it does not warrant recognition at this rank but is a variant of U. pumila maintained and known only in cultivation, and therefore best treated as a cultivar".

Elwes and Henry confused the tree, in their Synonymy list, with U. turkestanica Regel, which Regel himself had regarded as "a form of U. suberosa [:U. minor]". The Späth nursery of Berlin treated U. turkestanica Regel as a cultivar distinct from U. pinnato-ramosa and from U. minor 'Umbraculifera', with which Green considered Ulmus turkestanica Regel synonymous, naming it U. 'Turkestanica'.

'Pinnato-ramosa' grows very vigorously, and can ultimately make a large tree, however it also has a straggling, untidy habit, producing long shoots 0.60–0.95 m in length. Dieck also described the unusual arrangement of the branch and shoots: 'The branches are organized in a way that each offshoot lies in the same plane as the main branch or stem, like the quill and filaments of a bird feather'. The tree is chiefly distinguished from U. pumila by its greater height and more slender leaves. The leaves, which have pinnate venation, are 4–7 cm in length, ovate-lanceolate, with double-toothed margins, and finely pointed.