Mulch can provide a place for insects to overwinter, but unless you have serious problems with insect pests, I can't think of any other reason to remove it.

If you're in an area where it freezes in winter, mulch helps to moderate soil freezing and thawing, which helps reduce heaving of roots of perennial plants. It also helps reduce wind and rain erosion.

In my opinion (coming from the midwest with harsh winters and summers and clay), soil should never be left bare. It should either be planted or mulched. Your mileage may vary.

I will agree with the above 100%. Mulched soil is ALWAYS preferable to unmulched soil. The only time I would consider removing (and then promptly replacing with fresh) is if diseased plants were present and any of their parts have accumulated on the mulch/soil.

About the only insects that routinely overwinter in mulch are ones that would be present even without mulch........slugs, snails, some weevils, etc. and these should be addressed if present regardless of mulching methods.

Are we talking about an ornamental garden (trees, shrubs, perennials) or about an edible/vegetable garden? The approaches may be a bit different for each but both should have some sort of soil covering through the winter.

I intentionally mulch everything I can for the winter, using bark, grass clippings, and leaves.

you need better reading sources.. lol ...

some leaves... in some areas ... can mat down and cause an anerobic situation.. not allowing water and air movement to and from the soil ... the worst for me is maple leaves .... but in general.. all leaves should be removed from the beds.... though some are better than other ....

but alas... mine is also a midwest z5 experience. .....

but as noted above.. mulch stays...

perhaps this is clearer.. fallen leaves are NOT mulch ...

now is a great time to walk around local arboretums.. and professional gardens... pssst.. dont tell anyone.. but you dont have to look at the plants... look at how they are prepping their beds for winter .... and.. in fact.. if they have already removed the plants for winter.. all the better for your learning curve ... or volunteer at one ... they will teach you ... this would be a great way.. to get LOCAL.. SPECIFIC advice...

ken

Actually, Ken, leaves make a fantastic mulch in my gardens! I have never had a matting problem with leaves raked onto the beds. The bits and bobs of twigs are there to aerate the leaves. I had no idea that leaves could form an impermeable layer. I've mulched with leaves for ages and dare anyone to best my gardens with their store-bought mulch. BUT! It could be our different climates so please forgive my unfamiliarity with a different situation. Thanks for pointing out your experience with the leaves.

I only use shredded/chipped wood when the utilities have our trees mutilated. Then they run the branches through the shredder right into a pile on the lawn. After sitting through a winter I use them. No trucking in wood from who knows where.

As for the OP's question, my experience is that if you're using shredded or chipped wood mulch, leave it in place. Unless as already mentioned, there are diseased plants or overwhelming insect populations.

perhaps this is clearer.. fallen leaves are NOT mulch ...

What?? They most certainly are, if used that way. A mulch is any material that is used to cover the soil surface......that would include leaves, grass clippings, straw, ground up tires, bark, wood chips, compost, manure, carpet remnants, newspapers/carboard, lava rocks, oyster shells, etc., etc., etc. The list goes on and on.

Leaves can be an excellent mulch. In fact, they are considered a very desirable mulch in the UK and sold at a premium. In many cases they will break down completely over winter or at the very least, decomposed to the point where they are just a great source of organic matter to be workied into the soil (or left in place. YMMV). FWIW, fallen leaves are exactly what our local arboretum mulches with - free and a very plentiful source. Just don't let them accumulate on the lawn or on any walkways. They will smother the grass, often discolor or stain concrete and are slippery when wet. Which is pretty much all winter here :-). And larger leaves are best used shredded - just run them over a couple of passes with your lawn mower and presto - free mulch!!

Ken, maybe you need some better reading sources :-))

Here is a link that might be useful: benefits of leaf mulch

Mulches left on the garden can provide a bit of shelter for not just insect pests but beneficial insects as well, Contrary to what I have read about removing mulches from a garden I have seen only benefits by doing that, and people that have done the same on different soils tell me the same thing, the soil gets better faster.
Do not remove mulches over the winter and doo not till them into the soil, leave them as mulch.

In areas where freezing and thawing is likely over the course of the winter, try this:

Rake back the mulch and leave the soil bare until you have had some hard freezes. One really good cold spell to freeze the ground. Then mulch it thickly to keep it frozen during the warm spells.

In spring, rake the mulch back and let the ground warm up, then spread it back on the beds to save moisture and prevent weeds.

Thank you all for weighing in. I live just north of San Francisco, and we get a bit of frost but that's all. The mulch I was talking about is just for ornamentals; my raised veggie beds aren't mulched during the cooler months. It sounds like I can relax and not worry about removing or digging in! That's music to my ears.

My father always taught me to rake leaves off of grass but leave it in gardens as it provides needed nutrients for the soil/plants.

If someone living in an area where freezing temperatures occur and they rake the mulch off the soil and allow the soil to freeze and then rake the mulch back they will insulate that frozen soil so it will not thaw well in the spring. Put mulches in place before the soil freezes and leave it in place to protect the soil from the ravages of the winter wind, rain, snow, and wind.

I do not think the mulch does anything over the winter other than prevent soil erosion.

For my new beds lacking organic matters, I dig the mulch into the soil now (October) and turn the soil. I like the rain, snow or freezing to break the soil further. Some weeds may likely grow in the turned bed and I leave them over winter.

For my old beds, I just clean the beds, evenly spread the mulch and leave mulch in the beds over winter. Insects never a problem.

tommy, I'm in Santa Rosa and I cover all of my raised beds (that I'm not using for my fall/winter garden) with shredded leaves or cardboard. I find with our mild winters (except for last year with a couple of weeks in the teens!) if I don't, I get inundated with weeds!
Actually, I usually end up even using the leaves around the plants planted! Helps with the weeds!
My only exception was a couple of years ago I got a bunch of asparagus beetles! Last year I pulled back the leaves and gave them a spray of Sevin, then covered them up again. It seemed to solve the problem! Nancy

Soil, left uncovered and exposed to the ravages of the winters wind and rain can be blown away, eroded. Some of that will be the mineral portion and some of that will be, if its there, organic matter. Think back to the dust bowl days of the 1930's.
Even in New Jersey in mid winter there is some activity by the Soil Food Web in the soil protected from wind and rain. The only reason the freeze/thaw cycle might benefit any soil is of there is not enough organic matter in the soil. Keeping soil from eroding is an environmentally sound practice.

Do not worry about the soil exposed to weather. There are tons of grass seeds. Some winter seeds already come up nicely and they will hold up the soil well. And we are surrounded by woods, so no erosion problem at all. But clearly if this is on a slope, the soil has to be covered as soon as possible.

kimmsr ... You didn't read this part: "In spring, rake the mulch back and let the ground warm up, then spread it back on the beds to save moisture and prevent weeds."

I grew up in the Northern Rockies (Zone 2b, which is darned cold) and the worst shrub and perennial plant damage happens not from the freezing, but from the freeze-thaw cycles during the winter. The last thing you want is for a longish warm spell to warm up the roots and trigger sap flowing because the cold will freeze it in the stems and kill it.

For the tender spring blooms, folks want the blooming delayed if they can. This includes fruit trees, deciduous magnolias etc. Spring freezes can damage or even kill the blooms and trees.

But for regular garden, it helps to remove the mulch and let the soil warm by the sun. For certain plants, like beard iris, you want the beds very clean, so certain insects, like iris borers, do not damage the plants.

+1 on the last two posts. Well put.