I have a large canopy of cedar trees and wondered if I could safely put my pots containing bulbs under them for the winter. We have quite mild winters on Vancouver Island.
You can certainly overwinter your bulbs in pots. When deciding on the best location to do this, there are few things to consider, including the type of pots you have and winter temperature fluctuations in your area. Terra cotta pots – particularly those that are filled with soil over the winter – are susceptible to cracking due to freeze-thaw cycles. Anything that can minimize these fluctuations will help preserve the pots. As you mentioned, you have mild winters on Vancouver Island, so this may not be a concern. Your canopy of cedars may provide that extra bit of protection to keep your pots sheltered from sun and wind, which can not only exacerbate temperature swings but also dry out the soil. If your pots are darkly-coloured, protection from sun is even more important, as dark pots heat up faster and can trick bulbs into thinking spring has arrived early. If in doubt (as we know the past few winters have been anything but predictable!), you may want to consider storing your pots in an unheated garage or shed.
Regardless of where you decide to store your pots, you will want to make sure that the soil remains consistently moist, but not soggy. Prior to winter, check to make sure that your pots have good drainage — if they don’t, consider transferring your bulbs to different pots that have better drainage.