Clematis need a bit of pruning each year to keep flowering well. In the first year cut back all stems to 30 cm in the early spring before growth starts. In the second year cut all stems to 1m in early spring. There after, cut out dead wood and weak stems, and shorten the remainder by about 30 cm to just above a plump pair of buds in the early spring.
Tie in the plant to the support as needed, and fertilize with blood fish and bone in early spring and again in the summer.
Keep in mind when planting that General Sikorski is thought of as hardy, so this plant will survive close to or on freezing temperatures.General Sikorski will be happy in a south, west ,east or even north facing position, on well drained humus rich soil. Clematis like their heads in the sun but their feet in the shade
Soak the root ball before planting out. Dig a hole twice the diameter of the pot and deep enough to take the root ball buried, 7cm below the soil surface. Add some bolld fish and bone and infill with soil. Cover the soil surface around the plant with a mulch of gravel or organic material to shade the roots. Water regularly as the plant establishes.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as General Sikorski is a hardy plant.