Only wrap your palms before the cold weather begins (in Vancouver this is usually the middle of November) and remove it just before the weather warms up (in Vancouver this would be February). If one leaves the wrapping on too long you risk rotting the plants in the warmer weather of spring.
Palms do need protection for the winter when the temperature drops below –5 c. Even though the fronds can handle the cold, the problem occurs when the water inside the trunk freezes the new growth tips for the next year causing the ultimate death of the tree. Protecting your palms is a relatively simple procedure, which takes only a few minutes a year and will protect your plant in even the coldest of winter weather.
Pull up the fronds and tie them back. A simple rope or strong string is all that is needed.
Wrap a heat tape (they can be purchased at any building supply store) around the trunk- starting from the base of the plants – leaving the thermostat out at the bottom of the trunk. Make sure to wrap around the entire trunk up to and including the top of the trunk where the fronds are attached. A palm with a 4’ tall trunk should have a 15’ long heat tape to protect it.
Wrap the trunk with 3 to 4 layers of burlap making sure to tie it back with duct tape. Make sure that the thermostat for the heat tape is on the outside of the burlap. Wrap the whole trunk including the fronds if one has enough burlap. (If you live where there can be severe cold then wrap the trunk with bubble wrap or aluminum backed insulation for extra protection).
Once the trunk has been wrapped with burlap, re-wrap the trunk with plastic or shrink wrap (shrink wrap is the easiest to use and can bought at any stationary store). Make sure to wrap the entire palm including most of the fronds.
Once all of the above steps have been completed then plug the heat tape in and you are ready to go. The tape will only work when the temperature drops below freezing and will be enough heat to protect your palms for the winter months.
Caution: Make sure to plug only into a ground fault receptacle