When your clematis plants are ready to be planted outside, start by selecting a location in an area that has good drainage.
Next dig a hole as large as 18 inches deep and 12- 15 inches wide for each clematis that you are planting. When planting two or three clematis together, enlarge the circumference of the hole by 3 inches for each additional plant. Loosen the soil on the sides and bottom of the planting hole. Fill the hole with water to check the drainage, it should drain slowly but steadily. This helps hydrate the area around the planting hole in addition to allowing you to check the drainage. If your clematis plants are densely rooted, soak the root ball so that you can gently tease the outer roots loose, which helps them establish faster.
Fill the bottom of the hole with your amended soil mixture, and measure the remaining distance so that when you place the clematis ( type 2 and 3) in the hole, spreading the roots out like you would in planting a rose, and fill the soil in around it, they will be planted 2 to 4 inches deeper than they were planted at in the container. For type 1 clematis, plant to the depth of the container the plant was at.
Place your clematis in the hole on a slight angle with the stems going toward the direction you want it to grow in. this is important as the angle of the crown will help the plant produce new stems and eventually new crowns.
Backfill the soil, pinching off the leaves on the stem that will be covered with soil with the new depth you are planting it in.
Water the plant well, and prune off some top growth of the plant ( see pruning how to)