i live in the northeast. when and how do i transplant clematis?

Answer 1

The best time of year to move an existing clematis is while the plant is dormant before the new seasons growth begins - usually in late winter as long as the ground is not frozen. At this time of year the plant's energy is stored in the root system. Prune back the top growth to about 12 to 18 inches and dig at least a 12 inch diameter root ball as deep as possible.
Mature clematis roots can reach 4 feet down into the ground so the more roots you can save, the better. It is best to dig and prepare your new location before you dig up the plant to be transplanted. Dig a large hole, and dig it deeper than needed to make some room for compost or rotted manure in the bottom. You will also want to plant the clematis two to three inches deeper than the old level. One can use a post hole digger tool to get a nice deep hole. It is best to bury one or two pairs of latent buds, leaves and all, so that the plant can sprout from under the ground. It becomes a good insurance planting policy. The buried stem will develop roots. Before you place the plant into the new hole, throw in a handful or two of bone meal or other fertilizer high in phosphate to aid in root growth.
http://faq.gardenweb.com/faq/lists/clematis/2002090932004864.html

Good luck! Hope this helps.