How are things going? If what you planted is reliably hardy, no protection should be needed, especially if put in ground in spring. Where the ground does not freeze, heaving is not a problem. Attempting to keep plants that should go dormant in vigorous growth mode at the wrong time of year could be extra stress, not helpful. Unlikely in Z8 but worth mentioning. Couldn't tell if you are talking about plants in pots or in the ground? What plants? If you are zone-pushing Z9+ plants, I don't think I would use any kind of plastic. A pile of leaves is my usual method. Some paving bricks adjacent to the roots (on S side,) or dark-colored jugs of water, dark rocks, can also help keep the ground slightly warmer. Regardless of method, excellent drainage is usually a key factor in successful zone pushing. Wet + cold = rot. Dry + cold = exponentially higher chances of survival.

I have had no need to give roses winter protection, but I do need to protect some small young citrus trees, and the methodology might transfer. I bought a roll of concrete reinforcing wire, cut pieces of it that would roll around into circles large enough to go around the trees (usually about 12' of wire), then I cut off the bottom rung of the wire which gives me 6" pieces of sturdy wire that will push down into the ground. And then around that frame I put some of that light white fabric that the sell at the nursery for -- ta da "frost protection". In my case I also ran a set of Christmas lights under the bottom and around the trees to add just the slightest bit of warmth, so I have some funny looking white short towers around the property, but....hopefully I will still have some citrus. The concrete reinforcing wire has been my go-to material for lots of things: arbors, tomato cages, trellises. It is worth it's considerable weight in usefulness.

Karen B, I understand about the rain concern. Try to set up the frost cloth so that rain cannot collect in the cloth between branches. One year in CA, I constructed a PVC box around my largest plumie and covered it with a tarp. We had a good rain and the rain collected in the top of the tarp creating enough stress that the box collapsed and broke the plant into many pieces. The next year I made the box higher on one end so it had a sloped roof and the water ran off instead of collecting. With the frost cloth, you may want to put some poles under the cloth and between the branches to tent the cloth in such as way to encourage the rain to run off, rather than collect. Water is heavy enough to break branches if it collects. What I do is to spray some water on the cloth after I install it to see if there are any places it collects, then put a pole under that spot to raise it up enough. Good luck. Mike

Probably not rated for outdoor use.