Revive damage plants ??

Our local farm and garden center has an elderly gentlemen who has worked there for 40 years. I frequently ask his advise on gardening problems and have been amazed at his home remedies. But they have worked in the past but this time I have some doubts. I was there to pick up potting soil and vermiculite and the discussion started regarding plants we had lost due to our 20 degree nights. He said "Honey, if you put two tablespoons of Epson salts to 1 gal. of water and pour it on your plant after you cut them back, they will be just fine." I told him I had a greenhouse to put them in and again he said "they'll be just fine."
Now we all know that Epson salts is Magnesium sulfate and we are use to putting it on plants and veggies, but this is new to me.
If you have heard of this please let us know. I will try it on a mandavilla and an allamanda that I let freeze and I'll let you know what happens.
Gosh, I hate this cold weather !!

I'd be interested to know about this too... and how soon you have to apply it after the hard freezes.

I have been told it helps the cycads to come back after all the fronds have browned off from the cold. I was told to cut off all the brown fronds and pour a mixture of 2 T. epsom salts in a gallon of water around each plant. We will probably have plenty of opportunities to try it this year. It may just be an old wives tale but what have we got to lose.

Rock salt is used up North to keep ice from forming on roads. Could be a similar reason here, the combination of salt and water could keep the roots warm and prevent damege.
It'll be interesting to hear how your plants come through.
Barb