This charming clematis spices is quite different from the large flowered cultivars usually grown in gardens. The small pixie hat flowers make up for their small size by their numbers which appear from June through into autumn when they can be seen with typical feathery clematis seed heads.  While not as showy as the large flowered cultivars Clematis tangutica (Maxim.)Korch. is a lot less demanding than these tend to be. Like all clematis any reasonable garden soil and aspect is suitable and the small flowers and dense foliage make it more successful in exposed locations where the large flowered cultivars would be pull apart by the wind.

Its vigorous, dense foliage makes it an excellent choice of covering walls and fences. It will reach 4.5 m to 5 m but is not as vigorous as Clematis Montana which tends to rapidly smooth whatever it is intended to grow over. Left to their own devices it will grow quiet happily un-pruned but it can appear untidy. Alternatively they can be cut back as hard as needed in winter though this will delay the start of flowering the following year.

C. tangutica is very similar to C. orientalis L., the clematis grower Christopher Lloyd admitted he at times struggled to tell the two apart. The main distinguishing feature is that C. orientais has narrower leaves. Originally C.tangutica was classified in 1889 as a variety of C. orientais  by Carl Maximowicz a Russian botanist who travelled widely in the orient. Subsequently Sergei Korshinsky another Russian botanist placed it in a species of its own in 1898. It first reached the UK from St. Petersburg in 1898, but has since been reintroduced from its native habitat in Mongolia and North West China.

Reference:

Species Plantarum by Carl Linnaeus

Hillers Manual of Trees and Shrubs

http://www.tropicos.org/Name/27101612

Clematis by Christopher Lloyd

The Well-Tempered Garden by Christopher Lloyd