astilbe

Question

I have 2 in large pots and live in central Minnesota. Can I just put them in the garage and should I water them and cut them back?

Answer 1

Let the plants die back naturally.
When they have gone dormant you can dress the top of the pots with a layer of leaves or some hardwood mulch. This will help with moisture retention.
When they have gone dormant you can move them to the garage.
Check the pots once a month to make sure the soil has not completely dried out. You can add a small amount of moisture if needed.
The key to wintering is to make sure the temperature stays quite constant.
Not cold, then thawing.
https://www.gardeningknowhow.com/ornamental/flowers/astilbe/growing-astilbe-plants.htm