North is relative, but it is frost not snow which kills tree ferns, infact if we got snow i would not have to wrap them.

@Fernapple Here frost and snow kind of arrive together.

Dicksonia sellowiana

Rainfall, and when it comes, has a lot to do with it, most tree ferns need to be wet year round, yet if a ball of ice forms iin the crown, then they are dead. Some plants can not take ice at all and can only take low temps if it is dry, others need water from the ground so they can take air frost but not frozen soil. Some alpines can take overnight frost because they have natural insulation, but only enough for one night, if the cold goes on therefore they die. Other plants rely on snow cover and will die if the snow thaws. Some need low fall temps to get them dormant. It all gets very complicated, but then, that is the fun of the gardening challenge.

@Zoohome Mine are D. antarctica.

@Fernapple yep, the challenges we love to add to our busy life. ?

@Fernapple there is more luck growing yours in South Florida.
Enjoy it

I cover some things with leaves as well, and because winters can be wet in England and that will often kill many things even more that the cold, it is a common custom to place a sheet of glass at an angle over plants such as alpines and succulents to keep them dry.

@Fernapple
That's what I was thinking of doing with the voodoo lily but never did. You're right about wet feet on plants can do more harm than a constant freezing temperature. I've lost a lot of plants this way. Freeze and thaw over and over is what we're used to. The voodoo lily is the only plant I worry about now. I'm very diligent in the spring when it's time to remove its covering.

I have three, but they can cost one or two hundred pounds each, so it is worth the effort.