Are you trying to save developed flower buds? My one hybrid that has a white flower ready to open and another bud, is as limp as a wet noodle already. H. foetidus I'll just leave alone.
For a day or two, I would try it. But I wouldn't do it all winter. The few times I tried putting a plastic container to protect a marginal plant for an extended period of time didn't work out good. Both died.

I was going to try it just to get them through tomorrow and Friday - they've got buds just about to open and I don't want to lose them, if I can help it.

Sounds like a safe and reasonable effort to me, especially if you're careful that it doesn't overheat in the sun during the day. I don't know how much good it would do, with the lows we're expecting, but it couldn't hurt to put a few gallons of water in there to act as thermal mass.

Last winter a teepee made of bamboo garden stakes and some solar pool cover material (ultra-heavyweight bubble wrap) left over from the greenhouse insulation project was effective in protecting some over-eager buds on my tree peony. I placed three one-gallon milk jugs inside, and made sure to vent it on sunny days so as not to cook the poor thing.

I'm glad you brought this up - I'll be outside tomorrow rigging up some protection where needed.

My plants were ventilated also. Could be they were going to bite the dust anyway.

The water is an excellent idea - thanks.

My friend protected camellias and they died, mine in the same zip code did fine. My impression is that the hellebore buds should be fine. I guess we shall see.

How did your hellebores survive, njtea

Here is a hellebore that took the cold better than the rest. This one is near the meeting building at Frelinghuysen. Mostly the other hellebores went flat except for H. foetidus. It has a cultivar name "Old Early Purple" - Helleborus orientalis.

Unfortunately, Pontesmanny, I was quite ill for several days and didn't have the energy to get out and remove the protection on the hellebores until Sunday. They are still pretty flopped over so maybe my scheme didn't work. Guess I'll know if the temps get above freezing at my place today.

This msg is for njtea:

A few years ago, you sent 3 helleborus to me for which I was very grateful. This is the first time that one of the plants have buds and hopefully, won't get too cold and blossom. Would I normally cover them when the temps drop in our area in NJ? Currently, they have a few leftover pine needles over them loosely but they are covered with snow but it is melting. Do you use a mulch?

Vicki

Hi,Vicki,

I was wondering earlier this week if the ones I'd sent you had survived. I'm so glad they did and that they have buds!

Down where you are, I think I'd leave them alone.

I'm not certain that my experiment was helpful or harmful and with the weather that is expected up north here this weekend and beyond, I'm also not certain any of the buds will survive (unless we get a good snow cover).

BTW, I do still have lots of babies if anyone is interested.