United Kingdom 
i have a fireworks hydranga in a large pot which i have had for a few years but this year it has lots of healthy looking leaves but no flowers. I did trim it in the spring but would like to know why it hasn't flowered this year?
18 Aug, 2010
Trimming should be done right after it blooms, or else just a selective pruning to remove dead stems, and the remains of last year's flowers. Next year's flowers are forming right about now, so don't trim now, whatever you do. Since last winter was so ferocious, it may also have frozen off the buds.
18 Aug, 2010