I am going to plant some tree lilies in the mid of November. I live in London. I wanted to know if I can leave the pots with the bulbs outside as I have 12 large 40cm pots. I am going to bubble wrap the pots. Do you think that it will be ok or should I do something else? Thank you
Choose a sheltered location and add the insulation that you mention.
Also make sure you mulch the tops of the pots.
A garage location may be better if you have that option.