In theory, you should not need to do anything Emily but, I would add 3-4" of organic mulch up to the drip line and try to maintain 3-4" of mulch during the future growing seasons. It helps keep the soil evenly moist longer and protects the roots.

If you are trying to get early Spring bloomage, you may want to consider winter protection. Mopheads develop invisible flower buds in July-August by the end of their stems and Bloomstruck develops more in early Summer-ish. So if winter zaps them, you still get another flush with Bloomstruck.

But some people want to protect the July-August flower buds in order to get blooms in late Spring and for that, you would need to apply winter protection when the plants go dormant..

Since the plants probably have those round fertilizer pellets in the potting mix and since it is so late in the growing season, I would not add fertilizers until Spring.

If deer are a problem now and-or in Spring, the chicken wire used for winter protection may be ALSO given double duty to protect the shrubs' leaves and stems from deer.

I would definitely winter protect in your climate. Even though a "reblooming" variety, it's been my experience that these types of hydrangeas need to establish well in the landscape before that feature - flowers produced on current season's growth - is very reliable. And any early blooms ("spring" is probably overly generous - most macs don't bloom until early to mid summer in more northerly, colder zones) from old growth will most certainly be sacrificed to cold weather unless protected.