you can do summer cuttings, from the new growth, aprx five/six inches and pot them up, and stick them in a cold frame, i have had success doing photinia cuttings this way, always best to do quite a few just in case some dont make it, done properly you can achieve all that lovely new red foliage/shoots by trimming through the summer rather than just in the spring, however i give them one final trim early august so it has time to ripen before winter, and by doing so they get in on the act of all the other lovely autumn foliage, julien.

Yes, I read recently that June is a good time to take cuttings from shrubs as the material that you need is the 'semi-ripe' part of the stem...not over-wintered and not so soft that it can't support itself.