Looks like a hydrangea macrophylla. These can suffer from lack of blooms due to some of these issues:
* pruning at the wrong time - they normally produce invisible flower buds in late Summer to early Fall (July for me for example). So in July 2019, they produced flower buds for me and these flower buds will open in Spring 2020... unless granddaughter mows the plant. Then you loose blooms for the whole year. They will produce flower buds again in July of 2020 and these will open i Spring 2021. Some examples of these varieties are Nikko Blue, Merrit Supreme, etc.
There are some versions of macrophyllas that will now produce another batch of blooms later in the growing season, usually late Summer or early Fall. But, since your plant fails to bloom repeatedly, I assume it is not one of these. In commercial ads, they are sometimes called rebloomer hydrangeas. These may help you get some bloomage when weather is the culprit. Examples: Endless Summer Series, Let's Dance Series, etc.
If you happen to prune the plant between the time when they produce flower buds and Spring, you would be effectively cutting off the blooms and getting no bloomage. If this is your problem then try to prune instead before the end of June. Or better yet, do not bloom at all as hydrangeas typically do not need to be pruned if you you plant them where they can attain their estimated size at maturity.
If temperatures stay warm for a while during your winter months and then temperatures crash, the plant may break dormancy and that might kill the flower buds or the stems. The invisible flower buds are usually located at the ends of the stems. If this is your problem, water them plants deeply the night before temps crash, keep them well mulched (2-4" of mulch), use frost cloth for late frosts. If temps will go down a bit below freezing then consider winter protection.
Established hydrangeas usually do not need much in terms of fertilizers. If you are using large amounts of fertilizers or ferts that are high in nitrogen, the amount of nitrogen may get too high and this causes the pant to spend its time growing nice and big lush dark leaves and no blooms. If this is your problem, switch to a general purpose, slow release chemical fertilizer with a NPK Ratio around 10-10-10 once in Spring only. Or use 1/2 to 1 cup of cottonseed meal, organic compost or composted manure. Better yet, do not fertilize; just maintain 2-4" of mulch year around and let the plant feed off the decomposing mulch.
And don't worry about the plant. As long as the roots were not harmed, the plant will develop new stems and new foliage. But if it blooms on last year's stems, you will not get blooms this year. It will develop flower buds in the Summer of 2020 and they will then open in Spring 2021.
There are other hydrangeas that develop flower buds in mid to late Spring and then bloom. Consider adding some Annabelle-like hydrangeas or some hydrangea paniculatas. These bloom in late Spring to sometime in the Summer.
