Pink dogwoods turning white
Hello,
There are two possibilities for why your dogwoods have turned white. The first would be that it needs an application of nitrogen, however the second is the most likely. Pink dogwoods are grafted to a hardy rootstock so they can survive in colder temperatures, much like roses and fruit trees. I am asuming you reside in a colder climate where you have encountered severe weather which has killed the top and left the inferior understock. It is easy to tell if you still have any pink dogwood left. Examine that bottom portion of the trunk for the graft, it will appear to be a "growth" but if you look closer you can clearly see where the two trees meet. If you have any viable pink dogwood it will come from above this graft. If the growth is coming from below this graft, then all you have left is rootstock growth. This means that the pink dogwood part of the plant has died, therefore you will never get a pink flower again. Check it out and see what you got... I hope all is well and keep on growin'