I have some clumps of dianthus in the garden. The largest no longer flowers and has become very woody in the middle. Can I replant the outer pieces (which don't flower at the moment) or would I be better off taking cuttings and starting again? The ground is sandy and well-drained, because there used to be a patio laid on sand and some remains in the soil. We add compost regularly and I have also added some topsoil. Nevertheless, it is not the most fertile part of our garden. A more general question - are dianthus short-lived perennials, because they don't seem to last long in my garden? Are there are any particular keys to making them flower and last well? Many thanks.