I'm in PA and never mulched for winter. I guess if you have a perennial that is not commonly used in our area it wouldn't hurt. Our average plants are adapted to our freeze/thaw cycle. I'm no gardening expert, but I think mulching would delay the dormancy in the fall and accelerate the emergence in the spring. Making the plants more prone to a early or late freeze. The only thing I do on some first year shrubs/small trees is sometimes put up a wind barrier, depending on where they are located. Our low humidity wind in winter sometimes has a freeze dry effect on plants. It also keeps our rats with antlers away from them.

As long as the plants you are growing are hardy in your zone, they should be fine. Still, it is safer to mulch as it is always possible to get an unusually cold winter.

For plants that are zone hard and sufficiently established, not mulching has no impact on winter survivability. While mulching IS a great thing to do for any garden, many never mulch at all. It's a choice, not a requirement.

in a zone 7, freeze-thaw cycles are not the concern they would be in colder zones. Zone 7 soils rarely freeze to any significant depth unless a prolonged period of well below freezing temperatures.

https://www.gardeningknowhow.com/garden-how-to/mulch/mulching-plants-in-winter.htm

We are zone 5 - and never mulch the garden! We use bark mulch on paths and let most of the dead plant foliage - plus fallen tree leaves - remain in the garden beds over the winter, which acts as a mulch of sorts to feed the soil. As others have said, winter survival depends heavily on planting things appropriate for your zone - mulching to protect a special something that might not be hardy in your zone is probably best treated as the exception rather than something that dictates what you do for winter in the entire garden :-)

There is summer mulching and winter mulching. 'Summer' mulching is the normal covering of bare ground with something to reduce weeds, improve the soil, etc. It can be done in the fall, and I know many people who routinely do it then because that is when they have the time and the leaves. 'Winter' mulching is covering the plants to supposedly protect them from winter. In a climate that does not freeze solid, and has winter rains, winter mulching can kill plants by keeping too much moisture on the crowns of the plants. It's something that at this point in time isn't remotely common except for very special, zone pushing plants.

BTW, if you pay attention to the freeze-thaw phobics, you will understand that you should be living in a desert, completely devoid of all plant life, since freeze-thaw is just what winter is all about.

Recently planted/young perennials can be susceptible to freeze/thaw soil heaving, even in zone 7a (which features average wintertime lows down to 0F).

There are a number of plants in my garden that are not "rated" hardy in my zone 6b climate (including crinums, hardy abutilon, supposedly tender Salvias like S. guaranitica, Colocasia (elephant ears), figs and bananas) which benefit from deep mulching in order to come back every year. If a garden is confined to established perennials and shrubs considered rock-hardy in that area, one can probably get away without mulching in most cases.

IME it is a bigger issue with young, not yet established plants or semi-tender evergreens. Mulching their root zone/ drip line area could make a difference with those

I mulch with leaves to build and feed the soil.

Thank you everyone-this has been very helpful!