Helping perennials overwinter by not cutting down?

(Zone 4b)

There are many herbaceous plants for which one is advised not to cut back in the Fall thereby better ensuring survival over the winter. The two obvious examples are the "Butterfly Bush" and "Chrysanthemum".

To be honest I am not sure exactly why this would help these particular plants to better overwinter. My "hand waving" answer is that with upright stems, fallen leaves more easily collect and are trapped near the plant acting as mulch; similarly snow suffers the same fate ie accumulating amongst the stems again insulating the plant from the temperature vagaries one experiences from November to March. Does that make sense? Any other reasons you can think of?

But what is good for the goose should be good for the gander? That is leave all plants uncut to receive the same perceived benefits? Of course this action (or lack of) is not applicable to a diseased plant.

So I am one that more often than not does not cut back until spring.

What do you think?

This message was edited Nov 24, 2014 5:12 PM

Casper, WY(Zone 4a)

I cut all my perennials down to soil lever after blooming. I am in zone 4 and have never lost a plant by cutting down. I like to see my borders neat. Also raking is easier without dead plants in the way. I don't have time to cut back in the Spring. I do still have to do some tiding up but that goes faster. Actually, I enjoy cleaning up. The sun is out and temp is not so high.

I used to grow a Butterfly Bush. It is recommended to trim it back to 1" above soil. That is what I did.

Hardy mum I cut down to ground level also.

Consider also that bug finds a nice hiding place in dead plant material. Likewise disease.

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(Zone 4b)

Quote from blomma :
I used to grow a Butterfly Bush. It is recommended to trim it back to 1" above soil.

The usual recommendation one sees on-line is to not trim back until one sees the first sign of growth.

and it is a similar very common recommendation for hardy mums.

(But of course one can't argue with your success).

(Gorgeous picture of your mums by the way).

Casper, WY(Zone 4a)

Thanks for the compliment. I should have mentioned that cutting back in the Fall prevents accidentally trimming back new growth. I used to do it in the Spring and by the time I got to the end, there were to much growth that I had to cut around.

Foliage left in the Fall does not serve plants in any way except harbor bugs.

I wonder who came up with the idea of cutting in the spring. I know someone who uses a weed eater in the Fall.

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(Zone 4b)

"Foliage left in the Fall does not serve plants in any way except harbor bugs."

I respectfully disagree. As I had suggested I can see that leaving foliage up will allow leaves and snow to more easily collect around the base providing insulation to the many temperature variations one can experience in a true winter.

(And of course in the "wild" no one cuts back the foliage in the Fall ;))

Casper, WY(Zone 4a)

Whatever. Not worth arguing over.

Silver Spring, MD(Zone 7a)

I never cut my perennials back in the fall.

Last year I found so many praying mantis egg sacs, all over my garden. Pretty much every single woody perennial/shrub had either a praying mantis egg sac or spider eggs. Thank goodness we don't have venomous spiders here (except for the black widow, which has a distinctive egg sac).

So whether you cut back your perennials probably depends on the kind of garden you want. I don't use any pesticides at all, so it's important for me to have as many predators as possible. I also enjoy watching birds snack on seed heads.

But perennials that are completely herbaceous, with no woody stem? I think they just disappear on their own, except for hostas which can look really yucky after they freeze. This may be zone-specific as well. I still have asters blooming! :P

Also, butterfly bushes are shrubs/mini trees in my area, so they provide a nice bit of winter interest. We get a lot of freeze/thaw/refreeze throughout winter, with not much snow cover (depends on the year), which probably affects winter survivability. I imagine they'd prefer to be just cold and dormant under a mound of snow all winter long, instead of constant thawing and refreezing.

(Zone 4b)

This is my last season for BBushes on my property. I have probably had 6 of them in the past 5 years and none has survived past the second season. Clearly someone is telling me something ;) but I love this plant almost to the point of treating it as an annual! In any event I have provided extra protection this Fall to these 2 newest ones ("micro chip"). But if neither makes it then that is it for me with this plant!

Natick, MA

Sorry to hear that Rouge. I bought 2 starter plants last year and one has grown fairly well (not huge!) the first 6 months, the other not so great. I am curious if they will survive the winter. I DO have one in the front yard, it's surrounded by other "Adult" bushes and I think that gives it the "protection" I've read that it needs from strong, cold winds, etc. When I bought the starter plants, I didnt realize that it wasnt a hardy bush. Hope yours make it.

Hobart, IN

I don't cut back shrubs or roses until late winter/early spring unless it's to cut off hydrangea flowers that might bend a branch under the weight of snow. Our first freeze came early this year and a lot of shrubs didn't have a chance to drop their leaves. I will cut back the hardy mums to about 4 to 5 inches, leaving enough to catch leaves or snow. Most perennials get left alone until spring. I live in a wooded area and there's no such thing as "final" leaf cleanup so I don't sweat it. I garden organically (except for bigger poison ivy plants - I pull the small ones) and if what I leave on the beds helps in terms of organism activity and soil moisture retention, I'm happy. I've switched over to mulching with shredded leaves so not a big deal. Always a big spring cleanup but I'm ready for it after winter.

(Zone 4b)

'valal', here is the protector I am using. So one gets the "tent" and the other you can see right beside it has lots of leaf mulch.

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Beaver Falls, PA(Zone 6a)

Sorry to hear that you have problems keeping Butterfly Bushes coming back, rouge21. In my opinion, they are worth growing as annuals. I so enjoy watching the different insects visit mine during the summer. I did lose 1 over last winter. It was my Royal Red, that had been in the ground almost since we moved here 8 years ago. I have no explanation for that. It was well mulched as usual,as are all of mine. Another one, that was here when we moved in, a NOID lavender one, had tons of die back but a few stems did grow throughout the summer. This one is a monster and too big for where it's at, so I'm removing it next spring anyway.

I received a small Tutti Fruitti from a friend in Florida early this fall and planted it. It has bloomed constantly since it was planted. Hopefully it will make it through the winter. I'll report back if I lose it. I think it will depend on the type of winter we have - last year was the worst one in many years - and I may have planted it too late in the season.

Even with more moderate winters, we have lost two of the "Nanho" varieties, so I steer clear of them. One year, I lost a very large, Pink Delight, after several seasons. I have no idea what happened there, the same as with my "late" Royal Red. I have noticed that many of the "volunteer" Butterfly Bushes seem very hardy and make it through the winter, even if they are small. I have to shovel prune these in the spring.

Please let us know how your two Micro Chip varieties do and if they make it through the winter. And I agree. I never prune my butterfly bushes as well as many other perennials until spring, when they start to show some new growth.


(Zone 4b)

'Cindy', good point about branches breaking due to the weight of snow.

I have probably a simple question re something you had written about roses in your post.

I always cut back our roses in the spring as soon as I see signs of life on the canes.

But most of my roses are in a location to where we need to throw shovelled snow. The weight of such snow often breaks off the long bendy canes of these roses. I have wondered if under these circumstances if it is possible ie safe to cut back these roses in late fall thereby minimizing such breakage.

Hobart, IN

That's a tough dilemma with your roses. I'm no expert on them for sure but if you're sure they're pretty dormant by now, I'd cut just enough back to fit under a large rose cone to protect the canes from damage over the winter. Or maybe a big plastic tub upside down? I know they come in such attractive colors, right? ;) You'd have to add some ventilation holes to the plastic tub. I don't cover mine and they're not the best specimens but they're on their own root stock - not grafted - so I can prune the back pretty hard in the spring if I have a lot of winter damage like last winter. Perhaps a rose gardener would have better ideas for your situation. I was also wondering if a rose cone would help your butterfly bushes if you're really intent on growing them in your zone.

(Zone 4b)

Thanks Cindy for the reply. These roses in question have returned each year for the past 4 so they are hardy enough and maybe all that extra insulating snow they get from my shovelling helps!

Natick, MA

Rouge, is this the first year for your tent protection? If you used this before and still lost your butterfly bushes, I'd be at a loss...

Do butterfly bushes really grow that well as an annual? How big do they get? Do you grow them from cuttings?

This is totally switching plants, but has anyone had experience with wintering gallardias? I fell in love with my one plant I bought this summer, ever blooming til Nov! I bought 2-3 other varieties on sale from Santa Rosa in Oct. and am mulching with leaves hoping they will do well. Someone told me they lost them over the winter. I'm hoping my drainage is not an issue, and I plant to put leaf mulch on my whole garden bed as far as they will go (to not only keep plants warm/avoid heaving, but to help keep down the weeds in the spring and use the abundance of leaves afforded me..if they will all finally fall OFF the trees). I've been hindered by a toe injury the past couple weeks that I can't get do much.

(Zone 4b)

'valal', this will be my first year using this tent for a BB.

A couple of years ago I purchased via mail order Buddleia Flutterby "Petite Blue Heaven". It was far from an prized specimen when it arrived but it grew into a just fine BB by mid to late July and was outstanding by August and into September. And yet it did not return the following year :(.

This message was edited Dec 1, 2014 8:50 AM

(Zone 4b)

Linda, I will definitely report back next spring re the fate of our two "Micro Chip".

Casper, WY(Zone 4a)

There are several varieties of Buddleia, and many varieties of roses. In both not all are hardy in the North. Since it did not survive Buddleia Flutterby 'Petite Blue Heaven' was not hardy.

B. davidii is hardy to zone 5, yet i grew it in Zone 4 from commercial seed. I kept them for 3 years, then gave them away for I needed the space. They are perennials and don't grow as an annual. Height 6-8" in one season. They flower on new wood the first season from seed if stated early.

I have 9 rosebushes, all Floribundas that blooms all summer with a short rest in between. I also grow 6 mini roses. All are hardy to zone 4. They too flower on new canes so they get trimmed back in the Fall so that snow don't break the canes and the canes don't get whipped around by wind. This year I needed to thin out canes in the center to keep it open for maximum air circulation. I have had the same rosebushes since 2004. All got a drastic pruning to 1".

We had a extremely cold winter of 2013-14. Went down to -30 below during many nights. Not one rosebush was lost to winter. Even more surprisingly was that they bloomed up to October this year. Had more buds but we had temps of -10 which killed the buds and sent the plants into dormancy.

Roses have to be purchased according to their hardiness. With reasonable care they will survive in colder climates. I can't grow Hybrid Teas. and Grandifloras since they are not hardy for zone 4.

Valal The 4th photo are all Gaillardias. They are hardy perennials and come up every year to bloom all summer. They hold down the soil the reason my daughter allows them to grow at will. She is also in zone 4.

If you want to mulch wait until the ground is frozen. You don't want to keep them warm, which can't be done in your zone anyway. You want to keep the soil from thawing and freezing (heaving) for it is that which tears roots and kill plants that are not established yet. Mulching after soil is frozen will prevent that. On established plants mulching is not needed unless to keep weeds down. Newly planted perennials can benefit from mulching since their roots aren't established if planted late in the season.

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Perham, MN(Zone 3b)

I've lost plants that were cut to the ground and not mulched. Not often. But it can happen, with plants that are perhaps "pushing the zones," and especially if you're pushing the zones *plus* have abnormal weather. An example in my garden of a plant that should never be cut to the ground for winter is shasta daisy 'Becky.' Ditto for all heucheras. These plants will be damaged, usually severely, by such treatment, no matter what kind of weather the winter and early spring bring; and in some cases, they are killed.

On the other hand, I've gotten away with doing complete fall cleanup on most other kinds of perennials. It's absolutely *required* to clean up irises and peonies, for disease prevention. But for the most part, I choose not to try to get too much done in the fall. First because I'm way busy with my other job(s) at that time of year; and it must be natural for most plants to go into winter with their "clothes on." Second, because in the spring all the old stuff is so much easier to clean up, pack into the wheelbarrow, and haul to the compost heap. It's just way more compact, which means fewer trips. And the dead brown stuff can pretty much just be raked off, or snapped off by hand. I've done fall cleanup with an electric hedge trimmer, and to be sure, it's a heck of a lot easier than doing it all with my hand pruner (ouch), and wow does it ever look like a blank slate, ready for spring to write upon. But in the spring, I hardly need either device. Just a pair of gloves, pretty much. And it takes half as long or less to do the whole yard, than the time I'd have to expend in the fall.

Further, I like being out there at that time of year. I want a good reason to be out, to get my body moving and back in gardening shape. And attending to the details of cleanup gets the creative planning juices moving, makes me aware of issues that may be developing, and reminds me of things I noticed last year that needed to be divided, moved, or replaced.

I like the all-ready-for-spring tidy look of a clean garden in the fall. But. To tell the truth, snow is usually pretty reliable here, and hides all sins. And if it doesn't snow, why, having the perennials in their natural state really does help protect some of those crowns, when -15 arrives in mid-November, without much snow. (Uff da.) Followed by 34 and freezing rain in December. Think freeze/thaw. Without some kind of temperature moderator, like last season's dead growth, this has already been the kind of winter that I could expect to do a nasty number on lots of stuff, given there's only a sketchy inch of snow out there.

I don't have any problems with disease or pests, except for slugs, which seem to appear in cycles no matter what. And the way to deal with the latter is to bait first thing in the spring, for two or three weeks, starting before any damage is observed. The common pests that show up every summer, spider mites and aphids, seem to come whether I clean the gardens or not. So I don't think those "count."

Everybody does what they're most comfortable with, and what works reliably. I'd *like* to clean up in the fall. But there are decent reasons why, if I don't, it seems like it's OK. As it has turned out this year, so far, it's a good thing I argued "will I or won't I" for long enough that I never got around to it.

(Zone 4b)

Thanks so much "joanic" and others for all the replies. I love hearing what other gardeners are thinking and doing.

Quote from joanlc :
But. To tell the truth, snow is usually pretty reliable here, and hides all sins. And if it doesn't snow, why, having the perennials in their natural state really does help protect some of those crowns, when -15 arrives in mid-November, without much snow. (Uff da.) Followed by 34 and freezing rain in December. Think freeze/thaw. Without some kind of temperature moderator, like last season's dead growth, this has already been the kind of winter that I could expect to do a nasty number on lots of stuff, given there's only a sketchy inch of snow out there..

I think this does summarize very well what I am thinking.

And for us snow cover isn't nearly as assured as you get in MN. Last year our record setting cold was offset with almost record setting snow cover but snow is very hit and miss in my area and so I leave most old perennial growth as is and mulch lots with leaves.

Casper, WY(Zone 4a)

I think every gardener needs to consider what growing zone they are in before trimming back in Fall vs. Spring.

I probably would not in zone 3. But in my zone 4 I have not lost any perennials by Fall cleanup. Nor do I mulch. Snow is a hit and miss affair. It never last more than 2 or 3 days before it melts.

Come Spring, I still have to do some cleanup but it will be quicker.

(Zone 4b)


Well to my surprise the BB not tented survived the winter and is flourishing whereas the tented one never showed signs of life this spring. Now what I can't recall is whether I mulched each equally and then applied the tent :(.

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