I am new to site and not sure if this is where I should post this question? I just purchased a windmill palm and a yucca (not sure of species) for my deck. I live on the northern end of Vancouver Island and I am wondering if I can leave them out all winter of should I put them in my unheated greenhouse? Thanks, love the site so far!
Big pot (tub) may be adequate for palm most years if it does not freeze up solid. You don't want to have it sitting out in frigid winds, frozen. Yucca could be much more hardy than palm, or much less - it depends on what kind it is.
The roots are more tender than the leaves. Keeping the roots from freezing solid during an arctic snap is the hard part. Otherwise, they are fine for the majority of most of the winters we get. You may find that your unheated greenhouse is no warmer than the general outdoors, tho it will eliminate the effects of wind, helpful during those northeastern arctic wind outbreaks. I found with large potted borderline plants (phormiums in my case) I had to add some heat to keep them reliably protected from root kill. In the ground, these plants do fine except in exceptionally long cold spells, but the above ground container does not provide enough protection for the rootball. One option, if you don't have a semi-heated garage or other space, is to bury the pots in the ground during those coldest times. If you do bring them inside, be sure to get them back out as soon as the weather allows, so they don't try to start into growth in the middle of winter.
