Wilt proof for winter protection

It's a bit warmer this weekend, so late season garden chores go to the top of the list. This weekend is also when the Phactors traditionally purchase a nice fir tree for holiday decorating. The reason for this is simple; the trees have been harvested and won't get any fresher. While it isn't time to set up the tree inside, the tree is set in a bucket of water in our garage. If the weather accomodates, i.e., it isn't really cold, it gets sprayed with wilt proof. The commerical product is a waxy substance that makes a coating that slows down transpiration, water loss, and with a cut tree, it reduces needle drop, or at least slows it down. TPP has been asked a number of times if it's worth it to spray your broad-leafed evergreen shrubs because wilt proof (the commerical produce isn't spelled this way) is kind of pricy. In theory it works the same way; the coating slows water loss during the winter when it's hard or nearly impossible for plants to replace the water loss, so leaves dry out and die. TPP doesn't know the answer. Here in the upper midwest, broad-leafed evergreen shrubs seem to have a tough time; "winter kill" is pretty common among certain plants, e.g., rhododendrons. Of course, members of the heath family, the Ericaceae, hate our heavy, basic soils, so raising some of them is a fool's errand anyways. But back to the basic question. Is it worth it? If your evergreen shrubs have been doing OK over the winter, then it probably isn't worth it. But if you've been buying replacement shrubs, then it might be worth spraying them as insurance. Probably your best bet is to work on soil improvement so that the shrubs develop a robust root system. TPP will admit that he sprays his broad-leafed evergreen shrubs because they seem to suffer less damage over the winter. This falls short of an enthusiastic endorsement. It does increase the longevity of cut trees by reducing needle fall, but curiously, TPP doesn't know of any tree sellers that offer a spraying as an option (unless it's some hideous flocking). Spraying won't do you any good if you don't also protect your shrubs from hungry bunnies who turn into bark browsers if other food gets hard to come by.