I've had this clematis now for 4 years and it goes from strength to strength. Last year it was a mass of blooms which lasted from May to July. This year, due to the cold and wet weather it's still in bud, but there looks to be even more than previous years. I cut out all the old growth in February. I accidentally broke off a piece of new growth, so put it in a pot of compost and it's growing away happily. My soil is well drained, in full sun, and neutral.