We recently purchased purple rhododendron. It blossomed with several large purple/magenta blooms. We then had to cover it due to a frost at night. In the morning, it was still magenta. Went away for two days and upon return, all the blossoms turned pale pink. Why - from covering or weather?
Rhododendron Color Change
Certified GKH Gardening Expert
Did you keep the plant covered for the two days you were away? This would be the reason for your shrub's color lightening up, as it was cut off from the natural light it receives. When covering plants, you need to promptly remove the covering in the morning, only replacing as needed during the night. Throughout the day the plants should be left uncovered.