Non-flowering dianthus

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.

I doubt you will be able to split these successfully-but they do root  fairly easily from cuttings

Why not do both - take cuttings and split some of the outer bits off if they are rooted and replant.  Definitely one of the easiest plants from which to take cuttings and those root easily.  I just pull-off sections about 5 inches long with no bud and put 5 or 6 around the sides of a 5 inch pot filled with 50/50 sand and compost, then nip the tops off when they show signs of growing to make them bush out. Dianthus all get woody in the middle over time, so you do need to propagate from them every few years.  As is mentioned in another thread, they don't like acid, wet or heavy soil, but don't need a very fertile one.

I did a very lazy dianthus propagate. Mrs Sinkins got leggy so I spread her out and covered the woody parts in gravel. Looks like several plants now and going well. Might extend it further this year.

Thanks, all. Nutcutlet, great idea! Can I ask again, are there ways of ensuring that Dianthus do well? Would feeding them be a good idea? Or do they do better if they are in less rich soil? I have tried to find this information elsewhere but haven't had much success. Many thanks.   

Mine do best and last longest in my poorest driest soil but I sgree with Verdun about the cuttings. Not neccessarily yearly for me but as they start to look straggly. 

Thanks for this info. Obviously, then, they are quite short-lived as useful garden plants. I put mine in my poorest soil, too, thinking it was suitable for them, so I'm glad to learn that I was right about that .I'll remember to take cuttings regularly and replace plants. Obviously, it is better to plant plenty of rooted cuttings than to hope for larger clumps. A bit of information goes a long way!

Try putting compost in between the plant, to cover up the base of the shoots, leave till late spring and with luck these outer pieces will have developed roots of their own and you will be able to separate them and pot up in a sandy mix.

Wow! Great suggestion! Thuis is similar to Nutcutlet's suggestion above. I will most definitely do this! Thanks, Jayne11.