Ask Mr. Smarty Plants

Well, it is impossible to make a precise diagnosis without more information or actually seeing the plants but there are a few things that could be causing your problems.

You don't mention how old/large your oak leaf hydrangea is or if it has bloomed in previous years.  Oak leaf hydrangea rarely needs pruning and it blooms on new growth (its flower buds are set on the new growth in the spring) so you should be able to prune it in the fall without compromising the blooms for next season.  There must be another reason it didn't bloom (if it did in previous years).  If it was newly planted last year, it would have come from an environment where it was coddled so that there would be blooms on it in the garden center.  Transplanting it to your garden environment could set it back enough to prevent it from blooming the following year. 

Regarding your bittersweet vines:  if you in fact have a male and a female and if they bloom at the same time and if there is successful pollination and if conditions (light and moisture) are favorable for development of the fruit you will have berries.  So you will have to figure out if one or more of these "if's" is causing your problem.

Because your questions are both about plant culture, we really do recommend you contact a Master Gardener at your local agricultural extension office for assistance.