Answer: It sounds as though you are doing what the plant would need. It does well with sun as described (in your northern locale), an evenly moist yet well drained soil, and good fertility levels. You might possibly run some soil tests to be sure fertility is adequate. Also be sure to mulch heavily in late fall.
Apart from that, keep in mind that a new plant usually takes two to three years to settle in and become fully established before it performs its best so you may see some improvement next summer.
As you mentioned, this plant has received a lot of publicity and perhaps your expectations are high -- in zone 5A it is somewhat of an achievement in and of itself to be able to grow (and bloom) a hydrangea such as this. The special feature of this plant is that it is able to bloom on both old and new wood and thus potentially blooms over an extended season. This means that if winter damages the old growth, it will then bloom on the new growth of the season, so blooming starts later than normal. It also means the plant has to devote a portion of its energy to regrowth that can limit its strength in terms of blooming. In a more moderate climate where winter damage is minimal, you would probably see a much stronger performance.
I'm sorry you are disappointed.
Q&A Library Searching Tips