Yes you can grow compact hydrangeas in pots. You will have to keep the soil moist and within an acidic to slightly alkaline range to prevent iron chlorosis. Feed more often than you fertilize hydrangeas in the ground since all the watering will cause minerals to leech out thru the drain holes. When the plants go dormant, consider bringing them into a protected location for the rest of winter and then water them once every one or 2 weeks. Repot them if they show signs or outgrowing these pots.

I think compact is the key word. I put a 3 gallon 'Tardiva' in a 15 gallon pot in spring and I couldn't even get the thing out by late fall!

I have thirty plus in pots for years. They do fine. Like Luis mentioned put them in a protected area in the winter. I put mine under the house then bring them back out the minute the planted ES hydrangea by my back door starts to leaf out. I also add coffee grinds to my potted plants.

Thank you everyone for the feedback. I think I will bring them under my awning in about a month and cover them up. What do the coffee grinds do?