Prune clematis which flower in mid to late summer – both the pretty, small-flowered C. texensis and C. viticella varieties and the larger-flowered, more showy types like violet-blue 'William Kennett' and the lovely pure white 'Marie Boisselot'.
All these train beautifully through climbing roses, as both can be pruned at the same time. Start by removing all thin and weak stems, or any which have become damaged through the year. Then cut back the remaining ones by about a third, making sure you always cut to just above a pair of strong buds.
One good trick is to vary the stems by pruning them at different lengths. Cut some back by a third, but reduce others by a half: finally snip just a quarter of the length from any remaining stems. That way you'll encourage the plant to produce a huge, showy display of flowers from top to bottom.
Last but not least, set the plant up for the season ahead with a good feed and mulch. You'll find slow-release fertilisers like pelleted chicken manure and bonemeal in our garden centre: scatter a handful around the base of each plant, then cover with a 5cm layer of well-rotted farmyard manure to keep roots well nourished throughout the season.