July 3, 2015
What has killed our pinks/thrift/rabhan in Ireland? We have had pinks for years but came back this summer to find many scores of plants with a brown center that was a couple of inches wide that now in two weeks had browned the whole plant. My wife thinks herbicide must have been used, but our property manager claims they were killed by a lawnmower set too low. Is that an explanation?
July 5, 2015
Your description could both be a fungus issue or certainly the effects of a herbicide.
This any other plants in the area suffer losses?
If the lawn are treated with any kind of weed and feed product, which is very common, those contain herbicides which will kill flowers.
Here are a few links with more information.