Acer sinopurpurascens W.C. Cheng

Although an attractive and elegant tree that deserves widespread cultivation, Acer sinopurpurascens is extremely rare in horticulture due to difficulties in its propagation, possibilities for grafting being limited by the absence of related species with latex (van Gelderen & van Gelderen 1999). Neither is seed a useful alternative as it is a dioecious species and specimens are widely separated. A few arranged marriages might be useful. The red flowers, appearing early in the year and on young plants, are spectacular (le Hardÿ de Beaulieu 2003).

The male tree is at Arboretum Trompenburg, growing by the canal running through the garden. When observed in 2005 it was c.10 m tall (25 cm dbh) with two more or less equal main stems from a fork at 3.5 m. The branches are spreading and slightly pendulous, bearing the dark green, three-pointed leaves as a light canopy. This specimen was obtained from Dr Illa Martin from Germany in 1964, as part of a dispersal of stock following the death of her husband, but its ultimate origin is unknown (van Hoey Smith 2001). In England a female tree at the Valley Gardens is mentioned and illustrated by van Gelderen & van Gelderen (1999), but this specimen is not recorded by TROBI. That database does however record two further good specimens, a 5 m tree at Batsford Park, Gloucestershire in 2003, and a 7.3 m male individual at the Sir Harold Hillier Gardens in 2002. A few plants propagated from the Trompenburg specimen have been distributed by Esveld, but overall this is a good example of a case where a concerted conservation attempt is needed to propagate a rare and recalcitrant species. In Poland, a female tree derived from Shanghai Botanic Garden seed has been hardy since 1981 at Rogów and has reached over 7 m – but again, being a solitary specimen, it does not set viable seed (Tumilowicz 2002). The species appears to be unknown in North American collections, but its hardiness should be useful there.