I've tried saving Geraniums twice before. The first outdoor attempt was marginally successful. The roots and lower stems of two plants remained alive and regrew foliage and flowers the following summer. My second outdoor attempt was a total failure.
This winter I tried an indoor method. Because the cabin temperature can drop below freezing if we leave for an extended period, I'm cheating and leaving the plants in the condo in town. I'm trying the dormancy method.
Wait until the soil is fairly dry, then carefully remove the Geranium plant. Brush off as much dirt as possible, but do not wash the roots.
Pinch off any flowers, flower buds, or dead leaves. Wrap the remaining stems and foliage to keep the light out. The video used paper bags, I used newspaper lightly tied with the roots exposed.
Soak the roots in water for an hour before hanging upside down. Each month, soak the roots again for one hour and rehang.
I chose to place my Geraniums upside down in a plastic tub in the condo guest bathroom tub that never gets used.
The leaves will die, but the roots and lower stems should remain viable to regrow in the spring.
Here's a video by TheWeekendgardner on YouTube that helped me.
Here are my results. I lost two of the smaller plants. In early March, I put the rest into containers with lots of water to rehydrate.
Then Wayne and I left for a three week sun-cation in Arizona.
Here's what I found when we returned. Every plant had new leaves sprouting and they looked very healthy. Tomorrow they'll get planted in my cabin deck flower pots. With a little effort, I saved a substantial amount of money on this year's blooms. -- Margy