Not neccessarily. The only way to tell is to wait for spring. The Japanese Maple should be fine, as should any perennials hardy to zone 5 or lower. I don't know about the hollies and roses though. It would depend on the variety. How deep is your layer of mulch? How thick is the bubble wrap? Do you have them all close to your house?

The mulch is about four to five inches deep and I wrapped three layers of bubble wrap around each one container. They were across the balconey from the wall of the house,not against the wall. The perenials have all died back before now---will they be OK? Thanks!

As long as they don't go through a continual freeze/thaw, they should hopefully be okay. I've had mini-roses (not the tiny minature ones), with little or no mulch, survive up against my rail for about 4 years before they succumbed to being drenched in some mopping water that the person who lived above me would dump over the side of her balcony (thank goodness she moved last year). Plants like roses, etc., can rot if they stay too wet.

I usually leave first-year plants closer to the wall and anything zone 5 and lower stays where it is. Evergreens should be out of the wind (I am trying burlap as a screen around my evergreens - which I Wilt Prufed. The hardest part is getting plants through the spring warmups and late frosts when you'll need to cover any buds that try to swell or open.

We have an arctic blast going through right now and the forecast last night here was for it to go down to 18° F. Woke up at 5am this morning and the man said it was 12° F!!! I was like, WHAT?????????? Ran out and grabbed my lightly wrapped (with frost cloth) figs and brought them in. Everything else is winterized out there. I wanted my figs to get their 200 chill hours before bringing them in to wake up. Soon as the temps go up by tomorrow, I'll put them back outside.