Has anyone had any experience with Helianthemum? I bought two for the new rock (boulder) garden. One is "Wisley Pink" and the other is "Dazzler" (Red). Both bloomed great earlier this season (in late spring) and have grown considerably. Suddenly, in the past few days, the red one has all but dried up! The pink is just fine and thriving. There were no signs or no warning at all, no insects or anything else that explains it. Any ideas as to what happened are welcome. All other plants in the same area a fine.