You can start wrapping in burlap for protection if you wrap it at least two times. The more times you wrap it then the more protection it gets. But you also want the plant to get some air, water "through" the burlap. So a few days top is ok, specially if the plant has not broken dormancy yet. But if has foliage then you need to give it some sunlight and not keep it in the dark for long periods. I generally assume that protection will only give me a few degrees of temperature protection. If the forecast will go lower than that, my protection then will not help much.
I am exaggerating but bear with me: if burlap gives temperature protection of 2 degrees only but the temps will go down 10 degrees below freezing then burlap is not going to be useful.
My biggest problem when I see things being promoted in ads is that, very rarely, do they tell you how many degrees of protection you will get if you use the product (the burlap, a frost cloth, etc). Oh well. Enough with the complaining...
https://www.gardeningknowhow.c...
Hmm, that hydrangea does good work to block the view. If we can only be guaranteed that we will not be needing to order a lot of Amazon packages when the plant goes dormant in the Fall, that will be great!
F.Y.I.:
https://www.ajc.com/weather/ho...