Hello, Zab, and welcome to the vagaries of--to say nothing of varied opinions on--winter mulching. There are different reasons to mulch--to keep the ground warmer, colder, more moist or dry--and the whats and whens depend as much on the plants as they do on where you live and what type of mulch you have. With that in mind, I've got more questions than suggestions. Hope you don't mind. I don't want to sound confusing or discouraging--you've obviously observed carefully and learned a lot, and I have confidence that you'll do the right thing for your plants.

Let's see. I would not cut anything green. (Unless it's a bearded iris. If you have these, I'll be happy to do my Iris Borer Prevention song and dance for you--basically you need to cut the leaves and clean the beds each fall.) Definitely don't cut back the carnations; they tend to be evergreen, at least here in z6. If your salvia looks really bad, kind of like boiled lettuce, you can carefully cut away most of the wilted parts. But keep in mind that the crowns of many salvias stay green/alive over winter, and that the gross wilty foliage protects the growing part. Some gardeners leave most of their plants--all plants, not just salvia--uncut over the winter because the dead top-growth helps protect the plant from cold.

...Actually, what kind of salvia do you have? S. nemorosa, like May Night, with purple, blue, or pink flowers over most of the summer? Or, do you have the culinary one that's kind of shrubby? ( Don't cut back culinary sage at all at this time of year.) Or...?

What kind of bulbs are you growing? Is this foliage that appeared in the fall, or have they been like this all summer?

And a really important question: what kind of mulch did you get?

When did you put your plants in? Have you planted anything within the last 6 weeks or so?

How much snow do you tend to get each winter? Do you have reliable snow cover, or does the snow come and go? Do you get a lot of ice on the ground?

And, what else are you growing?

Winter is kind of a neat gardening season around here. As you've noticed, some plants stay green and look alive even during very low temps. It's wonderful to get to know your plants and figure out which ones do this. That way, in Feb., if you don't have a lot of snow on the ground, you can sneak out to the garden and see green things.

Amanda

Short answer: mulch now, and keep the material away from the plant crowns. And don't cut back anything except the few specific plants that require it.

Long answer on mulch: It doesn't just keep the soil warmer or colder, but mitigates freeze/thaw cycles, helping to prevent frost heaving of recently planted perennials. In fall it also delays hard frost permeating the soil so that plants can continue to develop roots. And it keeps plants from drying out during long dry or windy spells before the ground is frozen solid. At least, that's the theory.

Also, it's much nicer to spread mulch now while the weather is good - and if we suddenly start getting snow you can't exactly spread mulch over that.

Long answer on cutting back plants: Many plants that we call perennials are actually subshrubs, and should not be cut back until they've begun to leaf out in spring. The number of plants in this category is surprisingly large - including most herbs, gaura, and anything at all woody. Exceptions are plants that may harbor diseases in the dead foliage, like peonies, monkshood, and irises. Many people like to cut back hosta now because the leaves get slimy over the winter and become hard to cut.

None of this is to be taken as The Rule, it's just what I've observed over the years.

My short answer on mulching:
I keep mulch all year around and just add it this time of the year around the base of shallow rooted plants (az/rhodo/pieris/kalmia etc) I added during the current season. I also mulch fritillarias (both, imperialis and persica) after temperature overnight stand permanently below 30F.
Peony foliage MUST be cut and discarded, not composted, as it most likely harbor botrytis that next year will infect not peonies only, but all other surrounding plants.

Please, tell me more about cutting the foliage of Irises, siberian and bearded. While sibs and japs foliage look ratty anyway and I don't mind to cut it off, bearded iris foliage stays straigh and clean for me almost whole winter.
Why should I cut it?

My short answer on mulching:

This is such a bizarre weather year that everything I have is now mulched. In other years, I'd wait until the groud was frozen, then mulch to avoid the freeze/thaw that DtD talked about but that takes intricate timing.

Another reason: Because it is so warm I'm finding weeds starting to germinate. Don't want these babies to live so smothered'em.

And, The sooner the better or it won't get done (experience) :-)

Martie

George, Iris borers can overwinter inside the leaves of bearded iris, hence the advice to remove and destroy it. This thread reminds me that I need to get out there and get my cleanup finished. And the rest of the leaves before it snows.

Yes, I'm aware of the Iris borers, but if I understand correctly eggs will not start hatch before April-May, therefore removing and DESTROING previous year foliage could be done in March-early April to the same effect, thus allowing evergreen leaves be present the whole winter.
Am I wrong in my assumption?

Iris leaf-spot can also overwinter on old foliage.

Here is a link that might be useful: link

The advantage to fall clean-up of bearded iris, in my experience and in the experiences of those who taught me about it, is that it's *easy* to do a thorough job of preventing several common bearded iris problems if you do the work in the fall. Cutting the foliage enables a gardener to look closely at the rhizomes, the leaves and the ground around the plants. It's easier to see some things in fall than it is to see them in spring, and fall is a good time to make sure there's no scorch, leaf spot or rot on the plants.

Sometime between late Oct. and mid Dec. (depending on weather and when I happen to get around to it), I cut all of the fans on all of my bearded iris to about 2", sometimes even a little shorter. After I've done this, it's easy to see any leaves that died during the growing season. (This is a normal process for bearded iris.) Sometimes, these leaves are attached to the rhizomes but have fallen away from the fan. But usually, the dead leaves have already detached from the fans and are lying on the ground around the plants. These dead leaves are the ones most likely to carry disease (leaf spot, etc.) and borer eggs. After cutting the fans, I also usually see 1-4 outside leaves that are on their way out--they're still attached to the fans and still somewhat green, but they've begun to yellow or brown. I pull the dying (or even only just brown or yellowed at the base) leaves right off the fans every fall. One could do this in the early spring, yes, but with wet, snowy winters and many freeze-thaw cycles, the dead leaves tend to decompose--to a surprising degree--over the winter. It's a lot harder to find them in the spring. It's also a lot harder to find them (regardless of season) when the iris foliage is uncut, since the dead leaves tend to fall off in-between the rhizomes.

Jo is right about leaf spot. It's best prevented the way one prevents botrytis in peonies, by cutting off and disposing of diseased foliage in fall. Don't compost anything cut off of a bearded iris, except maybe the flower stalk.

I also use cutting bearded iris leaves in the fall as an opportunity to get a really good look at the rhizomes. I like to make sure that I haven't accidentally mulched over them or covered them with dirt (while planting something else nearby, or what-have-you), and that none of the durned norway maple leaves have matted down over or between the ehizomes. And it's a good opportunity to make sure there's no sign of rot before heading into a wet, cold period.

I love the evergreen iris foliage. But I've come to like the cut fans just as well, if not better, over the winter. They give me peace of mind. My iris increase rapidly, bloom abundantly and have no borers, soft rot/scorch or leaf spot--haven't for as long as I've been doing this fall clean-up (ca. 7 years, I think). I use no pesticides or fungicides on them. For a few years, I tried a "control group" of various bearded iris hybrids, which I did not cut but which I cleaned, as thoroughly as I could, in spring. Some were fine. But a number of them got scorch their first uncut year and several had serious borer issues plus scorch and soft rot during their second year. That ended the control group...no more problems.

So (again, in my experience), fall clean-up is easier and more thorough than spring clean-up, especially for organic gardeners and/or those who rely heavily on prevention of various plant ailments. If cleaning in the spring works for you, by all means, do that. But if you're new (or new-ish) to growing bearded iris, I'd recommend cutting the fans to 2" and cleaning up all dead or yellowing leaves in the late fall.

Amanda

Thanks Jo and Amanda.
I'm actually 'newish' to growing bearded (German?) irises due to the fact that full sun spots are very limited in my garden and the way my irrigation system installed I have no unwatered beds. And all of them mulched year around as well.
No wonder my attempts to grow irises were unsucessful.
Two years ago I planted a few rhizomes in a slightly sloping bed in hope that water will run off faster than irises will rot and miracle happens... they survived, grew and even bloomed for me the first time past spring.
I'm determined to save them and will do as you recommended.
Thanks again.

Thank you all for your feedback - I really appreciate it!

Amanda, to answer your questions:

I have May Night Salvia (purple)

The foliage is for spring blooming bulbs, mostly my muscari and glory of the snow(??), but some of the dutch irises I planted also sprouted up. (Up to 6 inches tall, some of them!)

I got a shredded bark mulch...

Most of the plants have been in the ground for awhile, but I did plant some hydrangeas within the six week period.

The snow doesn't usually hang around here (the gardens are all close to the house) but the gardens do get good drainage, so ice isn't usually a problem, either.

And, what else are you growing? That's a complicated question!!! Bulbs - daffs, tulips, crocus, muscari, glory of the snow, dutch iris, mountain lilies, etc. Plants - daylilies, columbine, siberian iris, bearded iris, azaleas, carnations, evening primrose, coreopsis*, salvia, sweet william, verbena*, hardy geraniums*, lilies, peonies, lilac -- that's all that's coming to mind right now.
*=truly young plants

Thanks for any further advice!