Try taking cuttings from the Dianthus and plant them out next year. There must have been a reason - for example bugs of some sort. Starting afresh, you may well get healthy new plants.

For unknown reason, thrips go for white flowers first, and when I hear "deformed and rotted flowers", they are my first suspect.

That could be why I've lost two Dianthus plants this year, Tug....both white flowered.

They hardly ever kill the plants, Spritzhenry. They usually just make the flowers, and occasionally the leaves, ugly. In biological terms, a fairly efficient parasite, but probably not wanted even by efficiency experts!

Thanks for the info, Tug - so I wonder why my two plants died? Our bad winter again I suppose. :-((

Many thanks for your help, will bug killer kill the blighters or do I have to dig up the plants and just keep the pink ones?

Provado does a good job on them. Not much else, since they are so good at hiding in the buds.

Thanks again for your help Tugbrethil..... I will give them a good spray and take some cuttings for next year.