I have what I believe is a Kolkwitzia bush in my garden (inherited when we moved in). This year it has only straggly branches and had very few flowers. It is about 6ft tall and has some arching stems, but looks pretty sad this year. Much of the wood seems old, although with white peeling bark it looks attractive. But what should I do to rejuvenate the bush. Gardening books say cut to grounds, but not when and how quickly qill it grow back.
Help and advice please.