Question about overwintering in pots
For those of you who have overwintered your hydrangeas in pots, I have a question:
I have 4 white out F&E's that I had in pots last Summer, and overwintered in my garage. I brought them back out and they are blooming like crazy. They are getting a bit big though..... How do I know when they have outgrown their container? I have them in a large 12 inch pots. White out is supposed to get 2 ft. x 2ft. Do you think I can keep them in this size indefinitely? (I'd like to!) If so, how many years can I go with the same soil? This will be their second season, so I am thinking I should add completely new soil..... But should I do this before I put them away for the winter, or when I take them out next Spring? Also, when is the best time to prune them down to control their size---they are the re-blooming type. Thanks so much!