Q.Redbud trees
I have 2 redbud trees planted about15 feet apart on my parking strip. They are about 3 years old and are about the same size. A couple of weeks ago they both got flower buds but only one of them has gone on to bloom. The other one still has the buds and they are not dry or dying but they are not opening either. I really don’t want to lose the tree. Is there anything I can do? Do I even need to be worried? I have attached 3 photos. The first 2 are of the tree I am concerned about. The third photo is of the other tree.

We did not receive the images.
Too much water can cause poor bud formation or the buds to be stunted or even drop from the tree.
Poor soil drainage can cause these issues and actually lead to root rot.
Redbud also need very little fertilizer. Even if you didn't fertilize the tree, other areas, such as the lawn nearby that was fertilized, can leach into the soil and effect a Redbud Tree.
Your Redbud needs a good 6 hours of sunlight everyday to bloom well.
Another problem is late frost. If the buds are developed and the temperatures dip they may be damaged and will not open.
https://www.gardeningknowhow.com/ornamental/trees/redbud/caring-for-redbud-trees.htm