Gosh that looks just like all mine! I wacked them all back and sadly did not get to enjoy their flowers. I have that same thing happen every year. I tell myself I will tear them out but then when I see them coming up in spring I just cant. I may just do that this year. Its rather sad and I sure wish I could answer your question.

Well, assuming that this is S. pratensis, or a related European Salvia, the stems seem to get flattened due to the weight of the flowers, heavy rain and strong winds. This happens with my plants every year. You MUST provide staking when the new shoots are only a few inches tall, so that the stems will remain upright and grow through the supports, though they will always lean towards the sun. (What's that in 2012 UK Summer?).

Robin, you MUST have many salvias that need more heat and sun...why don't you send them all over to my place for a vacation.....?..lol..

At my homestead it is always the dogs chasing lizards through the garden.