Q: I have a fifteen-year-old dogwood tree that has always had white blooms. This year it has produced pink ones. Why is this?

A: It’s not terribly unusual for a white-flowering dogwood to pop out a limb that has pink flowers. Growers select just such limbs in a nursery, graft them to the trunks of small white-flowered dogwoods and thereby make pink-flowered dogwoods to sell to gardeners.