It is called a mophead (hydrangea macrophylla).

It prefers well drained, acidic soils. Select a location with dappled sun or with morning sun and afternoon/evening shade.

The shade of colors will change as the growing season progresses until, in the Fall, they turn brown. Each mophead goes thru a different progression of color changes so see what this one does.

Provide soil moisture as evenly as possible with no periods of dry soil, followed by wet soil, followed by dry soil again. Add some mulch up to the drip line and give the plant 1/2 gallon of water per watering now and more during the summer months. When to water: anytime that a finger feels dry or almost dry when inserted to a depth of 4".

Because it is not acclimated to being outside, its blooms and leaves may react in different ways. I usually introduce new hydrangeas to the outside by putting them in bright shade first -while potted- and then move the pot elsewhere to get a few 1-2 hrs of morning sun and theeeen I place the plant in its final location. Try to get shade by 11am to 12pm in the summer time. If the leaves turn all yellow -including the leaf veins- and then start to brown out or if the blooms begin to brown out, use a chair to provide more shade: cover the plant with the chair or use an umbrella.

Too much sun can make the blooms dry out early and brown out. Lack of water too.

The shrub probably has those round fertilizer pellets so that will do for this year. In future years, give it 1/2 to 1 cup of compost, composted manure or cottonseed meal in the Spring and that should be enough for the whole year. Some coffee grounds, liquid fish or liquid seaweed are also ok if you feel like feeding it more but stop all fertilizers by the end of June.

Mopheads produce invisible flower buds in July-August and these then open in the Spring. In some years where temps are unusually cold or when temps fluctuate a lot, it may be necessry to winter protect them. Do a forum search for keywords like winter protect or winter protection,

If you planted it in a location where it can attain its size at maturity 4x4, no regular pruning will be required... except in mid-to-late May, when you can prune any stems that do not leaf out. Some stems get zapped by winter and you can prune these off at the end of May if you see no leaf out on them.

Some mopheads will rebloom later in the growing season. If yours reblooms, it may do so somewhere around the Summer months. These typically belong to the Endless Summer Series, the Forever & Ever Series, etc. Since your label was a "generic" label with no information, I would consider it a florist hydrangea. Some of these are tender winter-wise and require winter protection to bloom reliably every year but, others do just fine. I wish they would always state the name of the hydrangea in those labels!!! But for general purposes, whatever applies to a mophead would also apply to this one.

If you see signs that the plant is getting too much sun or you know that it is getting afternoon/evening sun, feel free to transplant it.

Good luck with the new shrub, Millby!

Luis