Last year, I planted several flats of pink erodium groundcover around my roses and in between my garden path stones. Over the past month, they have been dying off in droves. I've noticed that most of the dead ones are located in between the pavers where there is direct sun. Most of the live ones are planted close to the roses where they get some shade. Could it be that they can't take the summer heat? (It actually doesn't get very hot around here; the low 80's at the most.) The sprinklers have been going off every other day. The other option I was considering is that I recently applied finely chopped bark mulch to this bed. I was pretty careful not to cover the erodiums, but maybe somehow they got mulched to death. I don't know! Any insights would be appreciated.

- HershiGrl