on another branch the leaves are much smaller. on another branch the leaves are much smaller.
It looks like the rootstalk was allowed to grow. Grafted trees have a different rootstalk which is attached to a scion, or the upper part of the tree. I would cut out the part that doesn't look like the Pee Gee.
I had to remove a large oak tree which partially shaded them. Without the bid oak we get a lot more sun.
Yes, hydrangea paniculata leaves can stand full sun conditions in the northern half or northern 3/4 of the country. Only the southern states receive enough harsh summer sun where the leaves may appreciate some shade by mid afternoon or thereabouts.
That being said, the plant may need to be slowly acclimated to more sunlight levels. But the good news is that (a) in Long Pond, PA, Pee Gees should soon start going dormant and drop their leaves and (b) the levels of sunlight are decreasing with each passing day. When summer 2022 arrives, be prepared to water more to prevent heat stress. Maintain the plant mulched with 3-4" of organic mulch (no rocks) at all times of the year. I have used outside umbrellas, outside chairs and all kinds of contraptions to provide temporary extra shade in year 1 when acclimating new hydrangeas here in Texas.
ndividual blooms are sparse. Should I add a fertilizer with a high middle number? I've read adding phosphorus to the soil is bad for the environment.
The few Quick Fires (Quick Fire or Little Quick Fire) that I have seen do not have blooms that age from white to red. The blooms first turn white and as the blooms age, they begin a series of color changes that turn the white blooms several different shades of pink, similar to salmon. The blooms finally end up brown by the end of the growing season. Hydrangeas do not typically have the necessary pigments to turn blooms red although Quick Fire Fab tries to get closer with old blooms turning an intense shade of pink that I might call magenta at times. In advertising, I typically take bloom color descriptions of red or blue with a grain of salt as they can be shades of pink, shades of purples or a very weak form of blue. It is best to see them at a store to confirm. The Quick Fire Collection consists of a series of panicle hydrangeas that includes early blooming varieties so after the blooms emerge white, I suggest then waiting a few months (1-2?) to begin monitoring the bloom colors. The more intense pink of Quick Fire Fab is supposed to occur after the first shade of pink that resembles salmon to me. The length of time that blooms spend being a certain color can be variable and is affected by sunlight. I observe that whites will last less if they receive a lot of sunlight and last more if they get slightly less sunlight. So check often.
Consult with your plant seller, especially if a soil assay indicates no soil nutrient deficiencies or toxicities and the plant gets direct sun from sunrise to sundown. Consider too if you somehow obtained a mislabeled plant.
A lack of blooms may be caused by nutrient issues that a soil assay may clarify or by insufficient sun exposure. Panicles prefer full sun (much more than 6 hours of direct sunlight so sunrise to sundown in Pittsburgh) provided that their summers are not harsh like in Texas. Too little sun exposure such as morning sun only may yield sparse blooms.
Too much nitrogen in the soil, for example, would reduce blooms and provide the shrub with very nice, dark green foliage instead. You can normally use a general purpose, slow release fertilizer with a NPK Ratio of around 10-10-10 with hydrangeas as they are not typically heavy feeders. You can also use organic compost, composted manure or cottonseed meal. Ensure you only use the amount specified in the fertilizer directions and re-apply it -usually- every 3 months, not earlier. Start fertilizing by your average date of last frost (around the 1st-2nd weeks of May). Stop fertilizing 3 months before your average date of first frost (your average date of first frost is around the 3rd-4th weeks of October so the last application should be done around the 3rd-4th weeks of July). If using Holly-tone as fertilizer, the first application should be done at full strength. Then only apply it once more in late July but at half-strength.
Newly planted, young hydrangeas may take about 3 years to become more vigorous and stabilize color changes as the root system is still growing, which may look as no/little vegetative growth above the soil line or as fewer/smaller than expected blooms.