Hydrangea in a pot

I pulled this plant out of the ground a few years ago, intending to move it to another spot, but -- getting lazy -- I have left it in the pot. That makes for a strained bush, but the portability is convenient. This year, this "Limelight' hydrangea has sat on a landing of the steps from the garden to our back door. I took this picture last week, but it is there yet, still blooming despite near-freezing temperatures. In a week or two, I will move it down to a sheltered spot in the back of the garden, where it will stay till next spring.