Green leaves still can contain pests. In case you cut several hostas with viable leaves with the same tool without sanitizing (bleach) between hostas, then you could spread viruses and nematodes. I simply wait with cleaning the hosta beds until hosta leaves can be pulled off by hand without cutting. I remove all hosta leaves in fall. I then remove most large accumulations of tree leaves and then run a mower over it to clean the place, creating a little fine mulch, no large leaves. Voles will be active over winter and love to run underneath leaf mulch and eat hosta roots and crowns. Slugs will overwinter under hosta and tree leaf cover.

But people here have a lot of opinions.

A hosta might have a virus without showing it last year. This is my experience, and therefore, I am careful.

Good reminder about the viruses, thank you! I bought a lot
of new ones this year (good year for sales) so want to be especially careful. Thus
far I have not cut anything. The only reasons I was thinking about cutting was
so I could have little leaf stumps left over to be able to find the plant
later, and to get it done while it was not too cold out. I don’t want to put
markers in, they always get raked up by an enthusiastic raker here.

However…if not leaving tree leaves in place for winter
protection: do they need anything? I usually leave at least some tree leaves in
the garden (not buried deep) , thinking it would reduce frost heave. Is that
incorrect?

leave them till late.... when they are just a pile of gelatinous goo ... and just pull uo/out the jello like leaves... no real need to cut them

also ... took me decades... just leave it all there until spring ... hosta are self winter mulching in some sense.. if you dont have the rodent issue ....

ken

Thanks. Ken, are you saying to not pull the leaves at all? I have not seen any voles or other rodents. Maybe the local coyotes take care of those. Hardly any rabbits this year either, which is usually a visible sign that the coyote population is high for that year.

Don't forget the slugs which already have left their egg masses and themselves under debris in zone 5. Again, there are a lot of opinions here, whatever works out for you. I had hostas since 1990, but starting 2009 I bought many new cultivars and suddenly got viruses and nematodes, so I am tidy in fall getting rid of all debris. It is a lot of work digging out sick hostas including soil, don't need that stress.

Bernd That is distressing news as I have to leave my garden in Chazy before they have gone to sleep.i am hoping that an early ammonia treatment will due in most of the slugs combined with a spray of the Bayer advanced formula insect spray. Any thoughts?

I want to stay on top of the slug and bug issue for next year. I was putting
down slug bait all year anyway. By the time the damage was noticeable it was
too late. All new varieties bought this year were thick and slug resistant. I
had a lot of perforation holes that were not slugs, as there were no slime
trails. Even the thick leaved varieties had them. I never saw what was doing
it. I had a lot of earwigs but I don’t know if they are the culprit.

Is there anything I can do now?

Cleanliness in the garden will save you trouble in the long run as bernd said.

As your Hostas turn to mush or skeletons remove those leaves along with all other debris. I do a thorough fall cleanup and have little or no slug/snail damage. If I see any sign of damage in spring I put out tins of beer buried just under the edge of the plant. I leave approx. 1/8" - 1/4" of the lip above ground so that beneficial bugs such as ground beetles do not fall in. If you prefer slug bait that is up to you.

If you think you have earwig damage you can put out pieces of corrugated cardboard, say roughly 6 to 10" or bigger in the area affected. The earwigs will crawl into the holes in the cardboard and you can simply toss the cardboard and earwigs into a plastic bag for disposal.

Alternately, if you eat grapefruit take the half rounds you ate and place them with the cut side down in the affected areas. Dispose of in a tightly sealed plastic bag.

Earwigs are nocturnal so check and dispose of during the day, say at noon. (Whew, I do not usually type this much)

Thanks for the tips for earwig trapping. I don’t know what plant they might
target in particular, all I know is that I saw more than usual numbers.

It’s funny, I have always raked at least some of my leaves into the garden,
thinking I was doing a good thing, that they were providing winter protection.

There are few absolutes in gardening. There are those that say earwigs only eat decaying matter and they are getting a bad rap.

Leaves that have been shredded or chopped do make a great mulch that breaks down adding organic matter to the soil as they decompose.

Whole leaves can be a wonderful breeding ground for many pests and diseases. Lots of folks here do not clean up debris and are slug free. So many factors come into play.

Since you do have bug issues cleaning the garden in fall will really help. I am not saying you won't have any issues in the spring if you clean up this fall but after a couple of years you should see a major improvement.

In general for zone 5 snow cover comes early and stays late providing good insulation.

Ultimately you will choose from all the options and opinions and find what works for you. Fall clean up works for me.

I don’t shred the leaves: tried using the mower once and it
just made a mess. Winter heave is a big problem here, that’s the reason I have
been keeping them on thus far. The trees with big leaves are mostly bare now. My curly
willow is still all green. By the time those drop I won’t want to go outside
anymore!

I usually run my mower in a high setting over leaves which I did not get out yet of my hosta areas. That mower chews up also twigs and any remnants of perennials. These areas then have no thick mulch but just a coating. My areas where I detected voles get no mulch.

Here in zone 5 I am now able to pull off leaves on most of my hostas.