Hydrangea macrophylla: I purchased and planted 4 of these flowering shrubbs.?

Question

They are planted four feet apart in a partly sunny location.

They are approximately 3 feet in height and are looking strong and healthy. This is the first year for them.

Question: 3 of them are flowering and 1 has not even a sign of a flower starting yet. Why are 3 flowering and 1 is not.

They have been fed and watered regularly and are all in the same location.

Answer 1

Give it a little while longer.  It is a proven fact that when one plant is not doing well, the others around it will produce an actual medicine to help the ailing plant become better.  Go figure!

Answer 2

Even though they are generally in the same place there still could be something in the ground interfering with the growth of the bush such as roots, insects, etc. It's also possible this particular bush's roots are too high or too low in the ground.

BTW, My grandfather used to put a couple of nails at the root of these bushes to make them blue.