It could be hardy enough. But I would definitely grow it in a 5-gallon pot for a while so it can fill out a good root system first. As for the variety, it could be a recent one called Bela - at least that's what the color tones bring to mind. Check the soil line thoroughly to make sure there isn't an ID tag stuffed somewhere in there.

Supermarket hydrangeas are seldom, if ever, sold with any kind of cultivar label or identification. These are not intended to be landscape plants but rather are sold as flowering (temporary) houseplants.

Can they be transitioned to the outdoors? Sometimes - usually the results are much better if one lives in a milder zone. Because of they way they are propagated and grown, hardiness is always an issue. I would certainly not attempt to plant it out immediately. Like the other comments, I would pot it up and transition it gradually to the outdoors, then attempt to plant out later in the season (if that's what you want). And if you do plant in the ground, it will definitely need winter protection.

Push-in soil ID tags in Florist specimens run about 60% (in favor of) around where I live. This goes for seasonal gift-foiled ones at Walmart, one-time buys at Aldi, as well as regional chains like Giant Eagle. Growers use the soil tags to help sort and identify the stuff they're growing from cuttings as they go along, well before the plants receive any other goofy tagging, labels, wraps or foils. Searching soil lines (and risking looking like a maniac) at the grocery can really pay off in your favor, especially if you know which "gems" to look for or which color you're going to get from a specimen that hasn't bloomed yet (example: Regula = white). Either way, these specimens should be transitioned outdoors (pot in-pot out) over a period of about 3 years. Otherwise you will end up with a plant that doesn't die, but doesn't really achieve any significant size or blooming capability.

It's definitely a macrophylla. Could be one of dozens of cultivars. You can plant it outside, but if you don't winter protect it, you won't get many blooms in future years.

I actually read somewhere that the foil-wrapped, gift Hydrangeas that you buy at the grocery store and some big box stores rarely if ever survive past the current growing season, and if they do survive, you only get leaves, no blooms. Those type of Hydrangeas are actually specially grown in greenhouses and over-stressed to promote huge blooms on a small plant and it depletes all their energy for future blooming.

Depends on where you live and how suitable your climate is for growing hydrangeas :-) Grocery store hydrangeas are very easily transitioned to the landscape in my area. They will often skip a season or two of bloom as they become acclimated to the outdoors and resume a "normal" growing cycle, but they can and do thrive, grow and bloom for many years.

My Shooting Star florist Hydrangea is doing just fine in the ground (starting on its 4th year in the ground) - as good or even better than some of the garden varieties. Just because it is sold for the floral trade doesn't mean it has weaker genes, does it?

Anyway it doesn't hurt to plant it instead of tossing it unless you don't want to put a little labor in digging a proper hole. What have you got to lose?

I'm no expert, and I haven't tried it myself, I just read that somewhere. I'll have to dig around and see if I can find that article again. Good to know that people have saved them, kinda' made me sad that Hydrangeas would be wasted that way. =)

Bottom line is don't give up on your live plants, folks. In 2011 I nabbed an unnamed blue specimen in a 4" pot from my deceased grandmother's floral arrangement and it has bloomed every year since. Although it didn't get larger than 12x12" outdoors, I repotted it last summer to get more blooms. I suspect it might be Brestenburg or Enziandom, because it goes deep blue to construction paper grey.