You could always cover them with a frost blanket/harvest cloth but I doubt I'd bother. Trees have been experiencing temperature swings such as you describe since the dawn of time and they will adjust. Maples in particular have an ability to releaf very easily if the foliage as been compromised for any reason other than disease.

We're looking at 25, 23 & 21F lows the next 3 mornings. Not much you can do.

I'm looking at losing the lilac blossoms this year as they are already beginning to show up. They're pretty small yet so we might get lucky.

As long as your plants are 'zone hardy' they'll recover just fine once the warm weather returns.

hey tim ...

first.. understand.. this is normal life up here in ground freeze mi ... so just dont freak out ...

i dont think you said how established the plants are .. young doesnt mean much ... how established are the roots ...

small things.. get a few boxes form the grocer and cover them .. keep in mind.. ground temps are the important thing... the roots arent going to freeze and die .. besides the fact that those you list are fully hardy.. even up my way ...

taller stuff.. not much you can do ... prayer will help you cope..

the key is.. whether leaf tissue actually freezes .. breaking the cell walls in any given leaf.. if that happens.. the leaves will get ugly or destroyed.. most established trees.. regardless of age.. can and will releaf

snow is irrelevant .... ive seen it snow at 40 degrees ...

the forests regenerate themselves and there is no one around to worry or fret ... so dont make anything worse ...

if you cover anything.. you can not leave coverings on the next day.. you dont want heat to build up under such.. and cause more problems ... so you have to somehow be home to remove them when temps get to the mid 30s at least ...

crikey.. if you can figure out how to kill a maple.. let me know ... none of this is going to do it .. lol ...

ken

ps: if they are potted.. you didnt mention such ....