pruning small hydrangea plants

I had ordered some small annabelle hydrangeas, not expecting them to be as small as they ended up being. They have about doubled in size from when I bought them, which isnt saying much, since they were small to begin with and are still small now. I have one in a self watering pot, which it seems to love (I grow everything in those because they work really well for anything I think) and the other is potted almost completely in peat moss, which it also seems to love. They get bright ambient light in the window, but I am wondering if I need to pinch the tops down to encourage the stem of the plant to thicken, or do I just let it go? if I remove the small stick I have as support, the whole thing flops over, so I am contemplating pruning the whole thing down a bit to try and even out the root -to-foliage growth ratio (so to speak). Any suggestions?? Thanks!!!

I think they are beautiful plants, and this may sound silly, but I would pot them up and put them outside in a shade area where they can benefit from the heat and humidity. I don't know your future plans for them, but they will easily transplant in a high shade area. Just insure they receive daily watering while they are in pots. Potting up and cutting back won't do much damage and may (will probably) give you more stems next year. These type plants I consider to be "next year" plants.

So, bigger pots, and stick them outside? sounds good. I had not planned on putting them in the ground, since I am only renting the farmhouse I live in, and while I like the people I rent from, I am not going to give them all my beautiful plants! I have another hydrangea in a HUGE planter on the porch, and it seemed to love it there. Should I cut them down at all, or just let them be?