Last year I planted a Pilu clematis. It grew rapidly and was gorgeous for a few months. Then, all of a sudden, it dried up and died. I suspected it was accidentally exposed to Round Up although my other nearby plants (including an Ernest Markham clematis) were fine. This year I couldn't find a Pilu clematis to replace it with so I planted a similar looking Josephine clematis in the same spot. This plant never bloomed and is clearly dying. I also have a Blue Light (I think) clematis about 10 feet from the Pilu site. I planted it at the same time as the ill fated Pilu. The Blue Light died back last year too but came back this spring. Thus far it has produce three blossoms but looks like it's dying back again. The Ernest Markham remains splendid.

It is very common for Type II Large Flowered Hybrids to grow a bunch of foliage and then wilt/die down because they've outgrown their root systems and this especially happens when they dry out.

Earnest Markham is a Type III and not as prone to this behavior as Nelly and Blue Light are. Piilu has never been a wilter for me, in fact it has been excellent.

Plant Clematis in well worked and amended soil in huge holes that are heavily amended with compost.

Plant Clematis several inches deeper than they are in the pots from the nursery.

Cut them back when you plant too. Cut them back the first two or three springs. Pinch them as they grow too.

Keep them well watered and fertilize with organic rose or tomato fertilizer.

Expect several years for maturity.