Constance Spry only blooms once a year which means it blooms on old wood instead of new wood. Do not prune the plant till after it flowers... even then, if you don't know how to prune a climber you risk loosing some of next year's blooms. On top of that, it's a climber; climbers usually spend the first several years building biomass instead of blooming. Give the plant more time. It's an added benefit to train the canes horizontally to encourage more blooms, otherwise, if allowed to shoot upwards, you will only get blooms on the very tips of the canes instead of the whole length of it. If after five years it still doesn't bloom, shovel prune it... either it doesn't like your climate or you're better off growing something less finicky. By the way, DO NOT prune it like a regular Hybrid Tea, i.e. cutting all the canes down to one foot every autumn, that is a sure recipe for failure.