Actually, yes and no. Many of the older charts do not accurately list the USDA zones for growing clematis and/or those that tolerate shade. Edith over at ACS and some others have long been trying to get that changed... but I think many vendors are slow to come on board because they have not had personal experience growing each cultivar in a variety of conditions. I find the zone listings on the ACS database to be a little naive on how many will grow well in Zone 11 and the ICS database to be quite conservative on those that will thrive beyond Zone 9. Brushwood has done a great job of classifying the zones for theirs. For my own site, I have relied on a combination of personal reports, hybridizer info, and the ICS in posting my zone information. I relied on information from ICS for the aspect info.
There are few clematis that REQUIRE partial shade to grow well, but certainly some do... Silver Moon is a good example of one that will really hate you if you put her in full sun! But, most will tolerate some shade in their aspect. Again, there are always exceptions... Josephine will not be happy in shade! If you check out the COTW website, you will see that most have been listed as both sun and partial shade, but you can do an aspect search for those that prefer shade only. Here's a link:
http://www.clematis.hull.ac.uk... .
Again, just realize that the zones listed on the COTW site are incomplete for the zones. Also realize that for newer cultivars, information will be incomplete because the plant may not have been tried or reported on in a wide variety of growing situations.
