Summer Snow' has masses of creamy-white star like 1-1/2" slightly scented flowers mid-summer to mid fall on vigorous vines -- a truly spectacular scene when in full blossom during mid to late summer. It is a hybrid of C. potaninii var. potaninii x vitalba from the Ukraine. No pruning is required as blooms appear on the previous years growth -- giving it a particularly long bloom time. That is, you will get blooms on the vines from the previous year plus blooms on the new growth. You can, then, hard prune or light prune. 'Paul Farges' is another clematis we selected for the tall arbor. Not only has it reached the top but it is on the horizontal bars. The foliage endures hard frosts staying green for weeks when most other plants were gone. (PG3)