We had a wonderful large Dianthus erinaceus in our dry sand bed for about 15 years that was one of the first things that visiting rock gardeners noticed. As it grew over the years it expanded out on the top of the wall and it smothered other plants like Gypsophila aretioides but we loved it anyway. This big spiny cushion bloomed well every year but never set seed (The anthers did not appear to produce viable pollen) and I could never get cuttings to root so we knew it was only a matter of time before we would lose it. Most years it would get some dead brown patches that I would pluck out and it would heal up easily over the summer, but this year the dead patches grew steadily larger and the plant was dead within tw0 to three weeks. So our favorite Dianthus was gone, but this year a plant given to us by a friend came into bloom and replace our dianthus void. Growing nearby his spectacular young Dianthus myrtinervis ssp. caespitosus was spectacular.
I can only hoped it will live as long as our old D. erinaceus did.
I think we got our D. erinaceus from Siskiyou Rare Plant Nursery but they don't list it now but they do list Dianthus myrtinervis ssp. caespitosus.