Many tropical houseplants can suffer gradual exposure to chill with little in the way of obvious harm or damage. Actually though, a high % of tropicals, when exposed to even gradual chill below 50-55* lose a substantial ability to carry on photosynthesis. They sort of switch from getting their energy from current photosynthate production (the sun's energy) to getting energy from stored energy reserves - they switch from solar power to battery power. Since these plants are using more energy than they are making (no photosynthesis, if you recall), they are in a stressed state and in decline. The stress, unchecked, will lead to strain and eventual death unless corrected.

The former covered gradual exposure to chill. When sudden chill occurs, symptoms similar to frost damage can result as cells rupture and inter-cellular (inside cells) phenolic compounds leak into the intra-cellular (between cells) parts of tissues. When sudden chill shuts of the flow of a growth hormone (auxin) responsible for keeping an abscission layer from forming at the base of leaf petioles (stems), the layer forms and leaves fall.

Unless the chill was sufficient to cause the substantial death of more perennial tissues, the plant is likely to recover from its misadventure soon. The determining factor is whether or not the plant has enough energy to push a new flush of foliage past the (maturity) point where it will become a net producer of energy, rather than a net user. If the plant was in good health & seemed to be cruising through the winter in good fashion, its chances are far better than if the plant was barely hanging on.

We just went through only a day-long outage during a severe wind storm too, but a gas log in the fireplace and a substantial generator made it more like an adventure than a tribulation.

Wishing you the best of luck.

Al

I think Al as always has some very good points. I wouldn't think the temperature drop was really very fast, or you need to insulate! I grow abutilon outdoors here, and they seldom do more than lose a few leaves in our intermittent light freezes--even keep right on blooming. The answer may be partly in the quality of light they get too. Probably they'll look scruffy for awhile, but most should be okay. Be sure they get enough light tho'. And good luck from me too! (And moving to Louisiana wouldn't be bad either! I love it here, and so do my plants!)

Maybe I should have mentioned that 'fast' to a plant is different than 'fast' to us. Sudden chill to a plant is a drop in temperature that occurs so quickly that the plant cannot make internal physiological adjustments. A drop from 80* to 40* over 2-3 days would be a sudden chill; so would a drop over 1-2 days from 70* to 40*. Sami's predicament does qualify as a sudden chill, but the good news is that 40* is usually not low enough to damage the more perennial tissues. It usually takes the actual freezing of bound water (inter-cellular - water located inside of cells) to do that.

In Sami's case, the damage will most likely be in the form of an energy allocation setback. Whenever a plant loses foliage at this time of year (in Mass.) the plant calls on its energy reserves to make new leaves. Those new leaves are an energy sink (they use energy) until they are about 75% mature. Only then are they able to offer the plant a return on its investment.

What this means to the plant is a slow start when it wants to start growing in earnest (around the vernal equinox) because the stored energy it would normally use to initiate the spring flush of growth has been used to replace the cold-injured foliage.

Al

We had a similar experience in 2007. We lost our power in an ice storm for 5 days and although it certainly wasn't as cold as in Maine, it was cold enough for us. I don't think the temperature ever got below freezing inside the house as the outside temperature was (thankfully) in the high teens to 20's most of the time, but still it did no favors to some of my houseplants. It took a few of them a month or so to finally bite the dust and I wondered at the time what was going on until I figured it out. I can't remember all I lost, but some surprised me - one was a variegated ivy. I didn't think the cold would kill something like an ivy. The Christmas Cactus which died seemed more logical to me. It is a cactus after all. All the plants I did loose however were sitting next to a window. The ones in the interior of the house either recovered or showed no damage.......And an added curiosity - I have overwintered my Epiphylum Oxypetalum in my unheated attached garage for many years and I thought surely it had been affected since there was no radiant heat coming from inside the house to warm the garage up. But nope, it was totally unharmed by it. Plants are strange.........

Hello all
Just wanted to thank you for taking the time to post an answer. Your answers were very informative & I appreciate your good wishes. I have adopted a wait & see approach, I'll keep anything that looks even remotely viable until spring.
In the meantime we've had another ice storm & two more snowstorms & one coming tonight
Hummm Louisiana sounds good about now LOL
Sami

I strongly suspect that the hibiscus and flowering maples will be fine. Give them as much light as you can manage, and in the spring, if they still look leggy, prune them WAY back and put them outdoors if you can (move them over a period of days from shade to more sun or they will sunburn). Abutilons can survive down to 25 or 20 degrees F outside, and hibiscus can flirt near freezing. Hibiscus are notorious for yellowing leaves whenever anything changes from the status quo.