Fast-growing sturdy tree, a hybrid between A. japonica and A. subcordata. Initially, the branches grow straight up, later bending horizontally. Young branches are grey-green and older branches turn brown-green and have many lenticels. The leaf buds are on small stalks. The scattered, sharply serrated and dark green leaves grow to about 15 cm and unfurl purplish. It is oblong to ovate, appears early in spring and stays on the tree for a long time. The first brown-yellow catkins often appear as early as the end of January. Grows on all types of soil and is very hardy. Has no problems with (sea) wind. Alnus spaethii is a highly valued and frequently used alder found by Ludwig Späth in the Späth Arboretum near the Späth Baumschulen in Berlin.
Alnus ×spaethii 'Spaeth' rastie rýchlo rastúci a môže dorastať do výšky v závislosti od podmienok stanovišťa a klímy.
Správny čas na výsadbu stromu je mimo vegetačné obdobie. V strednej Európe môže byť Alnus ×spaethii 'Spaeth' so zemným balom vysadený od polovice novembra do konca apríla, avšak závisí to veľmi od klimatických podmienok a druhu stromu.