Clematis can be planted at any time of the year except during spells of poor weather or when it is frosty. To give Clematis a good start, plant Clematis during Spring, Summer or Autumn selecting a good weather spell and rain after planting is helpful, providing it is not a mini monsoon. This often means planting Clematis from April onwards.
The golden rule when planting a Clematis is to make sure that the root ball sits at least 5cms below the soil level - see image left. This is beneficial to the plant and helps to stop Clematis wilt. Dig a hole comfortably larger than the pot the Clematis is in. Make sure the soil at the bottom of the hole is not compacted, making it easy for the roots to grow into. Add peat free compost, fertiliser and water. Ease the Clematis out and place in the hole.
The easiest way to make sure you have got the depth correct, and to judge the depth, is to lay a bamboo cane across the hole so you can see the line of the soil depth and check the Clematis is at least 5cms below the soil level. Fill in, water and protect young growth from slugs. Clematis do well if their roots are shaded whilst the rest of the plant prefers sun, not an easy combination.
You can protect and shade the roots by the leaves of adjacent plants, such as a large leaf Hosta or by a physical barrier such as a slate, plus mulch will help to keep the roots cooler. In common with all new plants, Clematis should be watered well after planting. A newly planted Clematis will benefit from cutting all shoots down to 15 -30cms the first year only. Watch the Sunday Gardener video How to plant Clematis.
If you want to plant Clematis in a container, it is best to choose one of the less vigorous varieties. There are a wide range of smaller Clematis on sale, including those described as "Patio Clematis" which are ideal for containers. It follows that the large, very vigorous growers such as C. montana are not really suitable for growing in containers.