I'm not aware of how hardy this particular variety is ... though, to be on the safe side, I'd wait until the ground is pretty much about to freeze and then hill it up well with dry peat moss or even just garden soil. Shovel snow upon it as soon as it arrives and hopefully before bitter cold has set in. Leave the trimming to spring when you can see just how much live wood has made it through. I've seen varieties such as 'Limelight' with varying amounts of winter dieback and it still blooms well on new wood.

This Quickfire looks lovely all season. It is always blooming by Independence day, and it has flowers all summer, starting white and aging through cream to pale pink and ending with this rich pink, which it will hold until we get a freeze some time in late October most years. It usually has pale gold leaves for a bit as well, though it looks pallid compared to most of the autumn colors in NH.

They brown out earlier than mid to late bloomers here. Cool nights and sufficient moisture may help lengthen the whites and pinks. Hot temperatures will not help lengthen the whites or pinks. But yes, the early ones will brown out before the later/late ones here.. You can add late blooming Tardivas around the early blooming ones for a nice look of shrubs that appear to be blooming brown blooms (these would be the early blooming hydrangeas) around the white blooms of the very late blooming Tardivas. I saw a great photo online of this effect in a magazine but lost the link to it. I suggest you view the blooms to see if you personally think they might look unattractive as that is too much of a personal choice. But they looked great (to me) in that picture I mentioned. The panicle blooms of paniculatas and oakleaf hydrangeas are thicker than most other hydrangeas so they can hold the large blooms (although some end up flopping but the blooms do not fall down). As a result, they can remain a long time if the weather does not help to "disintegrate" them. You may have to deadhead them sometimes. I particularly do not like it when I get brown + white, where the brown blooms turn a darker brown, almost blackish color. The ladder sounds useful but I would make it a habit to deadhead PeeGees while they have no leaves so you can see where to cut more easily. You may go crazy trying to reach the very top thru all the foliage. Luckily though, that foliage should drop down in the next few months (or wait until closer to the end of winter to deadhead as, by then, most leaves will have disintegrated).

Once the blooms turn brown or turn a color that you do not like, you can deadhead the spent blooms. My deadheading preference is to let the spent blooms fall on their own and deadhead any stragglers in early spring. As for pruning, I stay away from pruning (1) at times when they begin to produce flower buds in late spring or early summer, (2) when they are actively blooming in the summer or early fall, or (3) in late fall as pruning might trigger new growth that can get zapped by early frosts. Your average date of first frost is around the 3rd-4th weeks of October so you might be able to prune if the paniculata is an early blooming cultivar whose blooms brown out well before this first frost date.