I don't prune my 'Quick Fire' since I want the size where it is planted. It is in almost full sun (just a bit of morning bright shade) and blooms well every year. My memory is that it didn't bloom the first two or three years from a tiny start - it just needed to get large enough. I think it is my favorite plant in a quite large garden, and without a doubt my favorite hydrangea of about a dozen varieties I grow. It blooms most year from the beginning of July through hard frost, and I leave on the dried flowers for winter interest. An all around great plant! June 30 From 2013 July 9 From clematis on hydrangea July 9, 2013 September 24 From 2013

You can Google image search for various states of bloom. All hydrangea paniculata begin mostly white and fade to pinks and browns. Both are "dwarf" hydrangea paniculata, as they aren't supposed to exceed 5' in diameter. There would be zero dieback down to zone 3. All paniculata are drought tolerant and require full sun in zone 4. 'Long as the soil stays moist and mostly shaded, little manual watering would be needed. Little Quick Fire just came out this year, so not many people have it. It would be a wise choice for mixed borders as full size QF (like mine) can exceed 7' in diameter. QF (a rare case) should NOT be pruned past early fall (when the leaves turn), and never after the plant begins to leaf out in spring - otherwise you will eliminate blooms before they happen. Little Lime is a top-rated shrub. Each spring, simply prune out tiny outer branches and leave the thickest toward the middle. There are no pruning restrictions on Limelight. QF stems are ruddy in color and have dark, rough, medium sized leaves. Limelights have much lighter stems and leaves (light green across the board).

They tend to shed some bottom foliage in the hot summer months, especially if bought now and planted in the hot summer months. Their root system is not that big so, monitor the soil by inserting a finger into the soil and watering -the soil, never the leaves so they do not get leaf spots- if the soil feels dry or almost dry. When watering, use enough water to get the soil moist at a depth of 8". It is quite rare for it to have small blooms as it normally blooms very early in the summer months so enjoy those few blooms. If they dry out and turn brown then so be it. Do not panic and let it simply use the nutrients to develop a larger root system instead. Make sure that the plant has 2-4" of organic mulch at all times, which will conserve soil moisture and provide future nutrients as the mulch decomposes. I would not fertilize it anymore and instead, wait until after all danger of late frosts has passed in spring 2022 to feed it again. All paniculatas are deciduous so it will eventually lose foliage in the fall 2021 but it will leaf out back in the spring 2022. Since the plant is not yet accustomed to getting this much direct hot sunlight (it was probably in part shade the plant nursery), consider providing some temporary shade in the afternoon and-or evening.

Sounds like it should've grown larger by now. Consider your soil conditions and any need to change them (richness, nutrients, mulch, etc). Otherwise it might need more time. Also, I've mentioned this many times on the forum specifically regarding QF: If you prune in August or any time after, you risk preventing next year's bloom depending on where you cut, so either prune immediately after the blooms turn dark pink - or - let it go all winter and cut off the spent blooms only (no other stems or nodes) AFTER new growth has begun. I think I pruned mine last july and it's completely loaded with buds right now.