Q: Four years ago I planted a red dogwood. The first blooming season it bloomed red, but in subsequent years has bloomed white. What’s up? How do I get it to bloom red again?
A: I’ll bet the red dogwood was originally grafted onto a white dogwood rootstock. In the intervening years branches from the white dogwood have vigorously sprouted and overwhelmed the red flowering branches.
If you still have some red blooms, you can remove all of the white flowering branches now and encourage the tree to sprout more red blooming branches above the graft union. Fertilize in April, June and September to maximize growth. Mulch widely under the tree and don’t neglect watering during drought.