Bonnie, I wish I knew what variegated cultivar I have, but the tag said only 'decorative yucca'. Anyway, I planted it in the ground the year before, and before its first winter it flowered, in spring it looked dead, but by summer it had offset 5-6 times. Our temps here can get to -25C or so, but I think what saves the yuccas is the snow pack insulating the plants from the cold, dehydrating winds that can come here any month in December. I'm happy to report that the first part of the plants' blanket was added this morning with 4 cm of the white stuff. Anyway, I'd cover it with burlap/snow until you find its hardiness, which should be at least a Z5, if not a Z4. And even then, keep it covered - IME, plants in pots are much more susceptible to freezing than those in the ground.

The survival of the piece has more to do with how the piece was designed and built, i.e. the types of glues and joints, and whether the joints can handle the expansion that will come with higher outdoor humidity, than with any coating you can put on it. Some pieces wouldn't fare well outside no matter what you did to them. An occasional splattering with rain won't cause your hutch to implode, but I wouldn't do this with a piece of furniture I was really attached to.

What is it made of, and where do you live? I've had a mirror that I made on plywood about six yrs. ago - hanging on my front porch, so it's sorta protected. It's still in good shape. Also have a cedar post - my backyard pedestal w/the turbine on top that's been outside about the same length of time. On the mirror, I don't remember what adhesive I used. On the pedestal I used thinset. I did have to re-grout the pedestal last fall - was showing cracks. Eventually it'll fall apart, but so far so good. Yours depends on the substrate and where you live. I live in E TX, where the weather isn't extreme - excepting last winter!!!!! Was awful. I did lose a terra cotta planter - was partially mosaiced. Other than that, things go through the winter here pretty safely.

To the zone 6 grower in Massachusetts. I commented earlier regarding temps. I'm in the Twin Cities historically a zone 4 but which is now a zone 5. A reclassification not that many years ago. The seasons are basically the same as they've always been; winters vary from year to year and summers do as well but any variation doesn't change too much with respect to Citrus in Minnesota. The Sun will still be at the same angles at the same times of the year regardless of anything else. While we suffer those short winter days, the flip side of long summer afternoons and evenings, especially around the solstice where it stays light until 9:30 or 9:45 maybe. Those endless summer days in the north produce more lumens for growth then you might imagine. It's just a party that's over by Labor Day or there abouts. I've grown Citrus for years where I didn't use any indoor lighting and the trees do fine once inside; they just go semi dormant or segue into a slow growth phase depending on how so you bring down the mercury. Currently, I cultivate my Citrus with flowering and fruiting in mind and if I wasn't using a HID lamp to augment the ambient light, it would be difficult to either get Citrus to flower indoors or to continue the process of fruit maturation if the tree had already blossomed and set fruit during the spring or summer. I would say Massachusetts is not as cold in the winter as Minnesota but cold enough and more damp. You probably get more heat then we do in the summer. I'm guessing maybe you are able to leave your trees out a little later than here in Minnesota and perhaps can put out a little bit earlier in the spring. If you are having any issues with your trees during those indoor months, (without knowing anything specific about their indoor growing conditions), just go for a high intensity discharge lamp and that will probably cure whatever ails you as long as you have a good airflow and are able to keep temps in the 60's. If you want any plant to thrive in the low light and short days of a North American climate, continental or maritime, particularly a plant like Citrus or bananas (which require lumens upon lumens), supplement any ambient light through windows with Either an HPS or metal halide spectrum bulb. The equipment is cheaper and more modern in the technological sense than ever. And regardless of anything else if you sit under an HID lamp for 30 minutes a day and you live in a northern climate in the US you won't suffer any drop off in hormone levels and the winter blues will be non existent. Some people have bigger issues with the short days than other people with respect to Energy and mental outlook. My attitude is make your plants happy between the months of October but particularly between November and the beginning of March. And make yourself happy at the same time. Winters are far easier to endure thanks to my 1000 watt metal halide converter bulb. Even if you're growing citrus strains that don't require the big time heat during the outdoor months, you're still going to more easily achieve continuing growth, flowering and fruiting ( with manual pollination) if you are using an HPS or a metal halide grow system to supplement. Ive had frustrating years with inadequate light. Even south-facing giant windows in Minnesota require some help. Even the greenhouses in the area whether theyre private or commercial still use giant hid ballasts to crank out Lumens. It's virtually impossible to give plants too much light this far north even with the greenhouse. After all despite any weather variations, the Suns low angle here never changes date specific.