Hi,welcome to g o y, I believe this is a variety of Dianthus caryophyllus, and as such is fully hardy, so you don't need to do anything special with it, you can take off the dead flowers to tidy the plant up a bit, Derek.

If they are border carnations just leave them alone. Sorry I don't know about greenhouse ones.

thanks for your replies Derek and Steragram. such a nice thought, not having to do anything, I might buy some more of these delightful flowers. Now I know why my granddad grew them in abundance.
Thanks again.