I have two tree rose of sharon both have lots of buds but only one flowers why don't the other one flower?

Question

I have two tree rose of sharon both have lots of buds but only one flowers why don't the other one flower?

Answer 1

Possible answers as to why your rose of Sharon flower buds are not opening, including:

Shade: Rose of Sharon will not bloom up to its full capabilities if given too much shade.

Rot: During rainy summers, rot can set in and ruin the flower bud (although you may not notice it from the outside). The same effect can be produced by excessive watering, if you water overhead.  

Drought: Conversely, during dry summers, rose of Sharon flower buds may be damaged from drought and fail to open.

These are the main reasons for your rose of Sharon buds not to open based on the information you gave my guess would be that the one not blooming is more shaded.

And we had a much wetter season this year.

I wish I could have been more help.