darmera peltata( umbrella plant)

I have never grown this type of plant but I would go with the zone 6 recommendation rather than zone 3. Your zone of 5b is close to zone six. I would think that your greenhouse, although unheated, would create conditions that are closer to zone six and would allow the umbrella plant to survive the winter. If you think it still won’t be enough to survive in a pot, you could put some hay bales around the pot as extra insulation.

-- "To forget how to dig the earth and to tend the soil is to forget ourselves." M. Gandhi

I think your right,the GH may be a better choice.These plants are really large and look great in a large planter.I guess this will be another experiment as it seems no one grows these to get info from.Oh well,thats what its all about ,learning through experience,right? Thanks for the reply.

-- Southwestern Ontario Canada Zone5b