Storing them bare root can work, but….. What are the winter temps like in the garage? Are the plants currently in the ground or in pots? I overwinter mine in their pots indoors.

Garage is very cold but not freezing. It might be 5 degrees or less Celsius. Plants in very large planters mixed with other plants. For many years, I have brought them inside and used grow lights because I don't have enough space by window, but I find many drawbacks to that including taking up room in my house, bugs emerging from soil, cats knocking over lights, leaves dropping all over the place.

If it doesn't freeze in the garage, then they should survive the winter. If you bring the potted plants into the garage, just stop watering them. When my father would save them bare rooted over winter, he'd either hang them upside-down (easier to tie that way) or lay them on newspaper.

Re your questions:

1. I wouldn't cut them back at all, unless they're damaged.

2. Just be sure to bring them in before a hard freeze kills them.

Thanks! Good to know.

I have to take them out of the containers, because I accidentally combined in there plants (not geraniums) with different requirements and so want to do the containers over anyway next season.

That's very interesting and good to know.

I stored about 10 barer root in my basement at about 50 F and they all died. What did I do wrong?

i tried this once also but nothing came back for me. I don't have ideal conditions here for them. It is just too warm in my house and too cold in the unheated garage. I may try to bring in a few ivy geraniums in pots and hope for the best.

That’s why I tried to recommend leaving them potted.

Most of the time they overwinter well for me just left outside. But I have held them overwinter indoors, both as a potted plant and by taking cuttings. Potted plants on a bright, sunny windowsill will continue to grow and even flower through the winter. Cuttings also tend to be very successful and can be done at any time and either rooted in water or directly potted up in small containers. Lot of online how-to tutorials.