Very timely post Harry. I've already cut a few canes off below areas where the cane was girdled by canker and everything above was shriveled. I've got a few canes where there is some spotting, but new growth above it. I'd hate to take it out.

I was going to start a thread asking if there was a cure for canker. I've started the Bayer fungicide regime, and I'm wondering if fungicides can halt the progression.

Interested to see others replies.

Eric

Cut it out? Hateful stuff,canker. It's painful to cut a huge cane back.

Carla

Ditto Carla 17. Even if the canker is arrested, I doubt that cane will produce the same quality blooms as the healthy ones. I read in one post here that certain types of canker are caused by the same spore that causes blackspot. So, in a way, it is blackspot of the canes. The difference is it doesn't just kill the leaf, it kills the whole cane, eventually.

Barbara

Once the canker/fungal mycelia (roots,sort of ) are in the cane, that cane will only get worse.
Downhere, a basal canker that is only a third of the way around a big HT cane will gird that cane by July, at which point, it's way too late to grow a replacement.
IF you can catch a canker when it's a single point on a cane, when it's after a small dead area of new growth (spring freeze damage), it's sometimes with the time to take an Xacto or other very sharp knife and cut the canker out.
But the situation cincy roses describes, "a few canes where there is some spotting, but new growth above it" is often canker throughout the lower part of cane and that cane will be a goner within three or four weeks. You will first see that the color of the cane above the spotting is subtly different, that it has more yellow and less green than the other unaffected canes on the rose. That yellow green color never gets better. Trust me on this. I've tried to save them with lots of water, great air flow, just the right amount of fertilizer for that sized bush....nil...nothing....their time is come and they die.
In our part of the country I think it's a necessity to grow our replacement canes in the spring so that they will harden off in summer. Replacement canes grown in fall seldom ever make it through winter. And so the replacements end up being replaced instead of adding to the vigor of the plant and making roses that get bigger and better each year.

I've evolved to looking for the healthy canes in spring. The ones that aren't healthy need to go. It's hard to cut off questionable ones. But if you decide not to cut, make it a learning experience. See if they make it through summer, with blooms, in your garden.
Some of us might get lucky and have heat come on fast. These fungi have optimal temperature ranges. They aren't active in cold weather and they are inactive or at least supressed in summer heat. This doesn't happen in my zone 6b, but it might happen to the south.

Good info, thanks Ann, out it comes. Another question...the cane with the worst canker I cut off right above the crown, there was no green below it...is it possible for canker to spread to the crown and kill the whole rose? This is all happening on my Sombreuil (own root), which seems to be a canker magnet this Spring.

(okay, sorry Harry, no more highjacking) :)

Eric

Canker killed two of my roses last year. Both roses had canker but good cane above the canker so I tried to save the cane. The canker spread and killed the whole rose. This year I'm going to cut out any canker I see even if I have to cut all the way down to the bud union.

Having this strange late winter early spring this year (very little sunshine, many cloudy days, drizzles and gumid, gray days) I got canker on almost every rose. There are roses that I cut back 3rd or 4th time. Cl. Peace is loaded with buds but canes get canker continuously.
I keep cutting and cutting canes and it seems to be a never ending process.

Even with fall dormant spray, canker is a fact of life for me here in the north. I think a lot of it springs from winter damage. I cut way back to below any canker and add the diseased cane to our orchard's burn pile. That means I usually start spring growth with 6-8" 'stumps' for canes, but the new growth ends up healthy and productive, so I guess it's O.K. Sometimes I wonder what it would be like to be in a climate where this isn't an issue, but I can't complain (too much!) since my roses do perform very nicely for me in the summer.

Very timely indeed. Here's my limited experience. Last year, my dbl ko was just peppered all over with canker. I waited 'till the forsythia bloomed to start pruning, but alas it was too late. The canker had already reached the root. I sp'd.

Later I realized I had missed seeing a spot of canker at the very base of sevilliana (I have a pic on my other comp). The rose had already started growing well, and the spot was so close to the union that I couldn't figure how to cut without injuring the entire plant, so I ignored it. Nothing ever happened. The cane continued to grow & put out blooms. Now I'll have to go back & review my pics from last season because the leaves may have yellowed a bit at some point but by then IIRC, it was so late in the season and so hot, I continued my regimine of ignoring.

I'm on my way outside right now to inspect further and to cut a huge center section of the new dbl ko because I see that canker crap again this year. Ugh. I did not winter protect dbl ko so I just think it's prone to canker. I'll inspect sevilliana and see if that spot got any worse.

BTW when you're cutting cankered canes, make sure you clean your pruners constantly.

Don't hit me! I don't get canker on my roses. I have sandy soil with lots of stones in it and I don't add anything to the hole when I plant a rose. I just top dress yearly with alfalfa meal and good soil plus a fine bark mulch. During the summer they just get watered. A friend of mine who has excellent soil, feeds, waters, mulches and then fertilizes again during the summer. She gets canker a lot. I am wondering if rose kindness can cause canker?

So, even if it is just a small spot, you must cut it out? Or off? Or do some of them just die out themselves?

Spraying with fungicide is a waste of time?

Crying? Complaining?

Some is canker, some is winter damage... scrape the cane on the black spot. If it is green under the black it is winter damage and you can leave the cane if you wish. (It won't perform 100% but it won't kill the plant either)

If you scrape and it is black or brown underneath, it is canker and you must cut below that to a green cane. Don't worry, it will grow back in no time...

I'm pretty sure I sprayed at least one of the roses with canker with a fungicide and it didn't help. The canker wasn't a small spot, it was a black band around the cane. I would say if you only have a small spot, and there is a good distance between it and the crown of the plant, that you can leave it and see what happens. But keep a close eye on it because it can spread fast.

To reduce canker I decided not to winter protect my roses. I think it helped. The weather is nice today so I'm going to prune and see what I have.

I have an epidemic of canker this year. I did not winter protect this year and all my roses survived, but all have canker. I pruned my three dko to the ground, some had black spots or ring at the very base, impossible to cut clean. I want to try to post some pictures to confirm the diagnosis. Decobug wrote that if after scraping there is green underneath it is winter damage. I did scrape and on many there was green, but I am not sure it was winter damage.
First this is like my dkos looked like, whole canes

http://i6.photobucket.com/albums/y214/mosypiuk/DSCN9898.jpg
http://i6.photobucket.com/albums/y214/mosypiuk/DSCN9897.jpg

In middle of the cane on the first picture you can see green spot after scraping.
http://i6.photobucket.com/albums/y214/mosypiuk/DSCN9899.jpg
These are canes from my blaze improved
http://i6.photobucket.com/albums/y214/mosypiuk/DSCN9900.jpg
and this is typical
What do you think?

I'm wondering about the canker on canes right at the crown. I cut off a cane on my Sombrueil that hand canker to the crown. There was no green below it to cut to.

My question...can canker be stopped by the woody texture of the crown...or is it just wait and see to see if it's infected the crown and killed the rose?

Eric

I get canker on my roses alot. I had a Neptune that got canker on 3 out of four canes, I got so mad and thought oh what the heck, I'm probably going to lose it anyway so I soaked it in bleach and water for about an hour. Re-planted it and cut the canes with canker down to where it was mostly green. That was two years ago.This Neptune bush is now going on 7 ft. tall.

This is my FIRST year with NO CANKER!!! My roses usually get a lot over winter. This year I shoved plastic bags filled with shredded paper under the branches and close to the stalk. I couldn't believe it when I took away the bags this spring - NO CANKER!!!! Happy Dance!!! I think it's because the canes stayed dryer.

Carol

I am reading this thread with interest, and am not sure about the word canker.

I also have been experimenting with not pruning, but allowing the rose to grow, then cutting back in the summer.

I realize that we have been rather careless in the past, and have not taken care of damaged canes. Sometimes canes have rubbed canes from other bushes, and those damages may be canker.

My question is, how can you identify canker from blackspot or winter damage, and what is the difference between cutting out the cane, and letting it go. If there is canker at a certain point in the cane, from that point to the tip of the cane, that cane is gone. If you wait to cut out that cane, will it in fact infect the rest of the cane, or will you simply see the damage later that has already occurred? Does canker positively spread? Is that a fact? Or is the center of that cane damaged, and it takes a month or so to see what has already happened?

In other words is it a necessity to cut that cane and others that are infected, or could those canes be a part of the photosynthesis and other growth mechanisms that would be instrumental in aiding the rose to create more basal shoots? In my garden if I cut the rose down to a foot or so, it often takes forever for it to begin to grow. But if I delay the pruning, I am thinking that the weak canes can aid in the absorption of nutrients needed to create a more healthy rose.

I would like to know if the diseased cane will destroy the plant, or if the disease will simply hurt what has already become contaminated?

Sammy

If you have a small canker on a large cane, try cutting it off with an Xacto knife or single edged razor blade. But first check to see that there aren't lower cankers on that same cane.
Winter damage is a cause. Canker is a disease with symptoms.

Canker is a collection of different fungi.
Fungi have optimal temperatures of maximum growth and often when summer comes, the fungi on and in canes go temporarily dormant. BUT those fungi are not killed.

On top of these fungal cankers, there are different fungi that can and do land on dead plant tissue. The general name for them is saprphytic fungi: dead eating fungi. I think some saprophytic fungi have the ability to further kill the plants. I've seen a symptom that some of us here have called creeping black death affect canes and then move eight inches down a cane and kill a grafted rose in eight days.
But there's not much in literature about the fungi affecting roses, beyond Black Spot. Other fungal problems are in the scientific literature but are predominantly about the diseases of roses grown in greenhouses for the cut flower trade.

My question is, how can you identify canker from blackspot or winter damage, and what is the difference between cutting out the cane, and letting it go.
Black spot is small and as I understand it not that invasive. It can overwinter on the cane in small areas. It's not in the best interest of BS to kill a cane or a rose.
Winterdamage is physical damage to canes. Into those damaged areas, fungal spores can come. (And the spores come from our mulch, where 'good' spores are breaking down plant material)

If there is canker at a certain point in the cane, from that point to the tip of the cane, that cane is gone. If you wait to cut out that cane, will it in fact infect the rest of the cane, or will you simply see the damage later that has already occurred? Does canker positively spread? Is that a fact? Or is the center of that cane damaged, and it takes a month or so to see what has already happened?

In some cases, cankers are localized, and they are at leaf buds where early growth happend, was zapped by a freeze, and then rot started there. More insidious are places where there is rot all up and down a cane. This in my garden seems to happen on canes a half an inch or less in diameter. I'll see something sort of high and then looking at the bush from the other side, I may see it two places lower as well. When I cut that cane off, often I'll see tan/brown pith all the way down the cane with it worse at the visible cankers. I'm not sure if they are related or if the cane was weak and canker-prone and one quickly sloughed off spores that found a nearby home.

In other words is it a necessity to cut that cane and others that are infected, or could those canes be a part of the photosynthesis and other growth mechanisms that would be instrumental in aiding the rose to create more basal shoots? In my garden if I cut the rose down to a foot or so, it often takes forever for it to begin to grow. But if I delay the pruning, I am thinking that the weak canes can aid in the absorption of nutrients needed to create a more healthy rose.

I've left questionable canes on only to loose them midsummer. And their fall replacements don't make it through winter. I think the key to a 'well tuned rose garden' would be to know when in the spring to cut back for optimal rebound growth. Sometimes here, that's February. (There are times I wish I lived on an Island with a more moderate and predictable climate). Feb pruning also is before the stem borers come out, and pith hardens so the borers can't get in, so no sealing.
My growing conditions aren't great at midsummer. If they were, your reasoning would make for better plants. But very hot summer days don't make for replacement growth here.

I would like to know if the diseased cane will destroy the plant, or if the disease will simply hurt what has already become contaminated

Some diseases of canes will spread and kill; most won't. But getting a rose to keep good leaves through summer is what we want. Those leaves have to come from healthy canes or they drop.
On a few roses look at the colors of the canes. Good healthy canes on HTs are a clear green. Then there are the greenish yellow canes that won't be around next year, even if there's no canker, the rose has already decided to abandon them. What we need to do is learn to watch those going to be dead canes and see if they do enough good to merit their retention or are they just reducing air flow and make the bush more susceptible to fungi.

My slightly more that $0.02 based on lots of learning mistakes made.

Thanks for your input Ann, it's that type of experience we look for here on the forum. I'll have to snap a picture of my Sombreuil, and also an Eden that I'm concerned about (picture worth a 1000 words). The Sombreuil seems to be lagging behind, and I'm concerned that canker has infected the crown, and the seemingly healthy looking canes that remain coming out of it.

It's harder to tell because these canes have already developed a woodier exterior since they are a bit older. I assume that canker kills the cane because it inhibits the flow of nutrients that are carried in the green part or "bark" of the cane...like a tree?

Eric

I m sorry, these are the pictures in the same order. What's your opinion?

{{gwi:246792}}

{{gwi:246793}}

{{gwi:246794}}

{{gwi:246795}}

I am not an expert on your first problem. I have that in my garden on Graham Thomas and Pat Austin. Every Year. And the canes remain productive, although I know they could do better. The first two pictures are of fungi that don't gird or kill. (I think the purple rims indicate they are currently active.)
Third picture: fungi have come in and colonized where fresh spring growth was killed by early freezes. These will gird and the canes above them are goners. I had a Graham Thomas stem five feet long one year with thirteen death spots like these. The only thing you might have been able to do would have been to finger prune off the leaf buds just as soon as they were killed. Leaving them there let the fungi in.
FOurth picture: canker where a stem was cut off last year. Would probably have girded that cane by July. It was spreading. Stem below it looks good and healthy (That's a good sign.)

mosypiuk, look at the location of the spots on your roses. You can see that it is entering the canes at the bud eyes. Just my crazy opinion, but in my experience, that stuff can be virulent. I'm not sure that's canker. It could be a bacterial infection or a fungal infection. I had it in a very, very wet spring. It killed canes feet at a time.

1) Practice extreme pruner sanitation. When you prune those cuts, dip your pruners in undiluted household Lysol for at least 3 minutes between cuts.

2) Prune very hard, six inches below any infected bud eye. Soak pruners between cuts.

3) Never prune in the rain. Whatever this is may be water-borne and spread by wind driven rain.

4) If you have an arsenal of bactericides and fungicides, I'd try all of them, in rotation but beware of adverse interactions. You will need to study your chemicals to do it right. It's hard to know whether there is one thing going on or different things. Once a rose's canes are diseased, they are more likely to get other diseases. Fungicides will help with canker. If it's downy mildew, then Aliette works but does have labeled adverse interactions.

5) If you haven't pruned all your roses already, suspend pruning any unpruned roses until this is under control.

6) Practice maniacal garden cleanup: Not one spent bloom, not one pruned cane, not one leaf from last year. Rake it all and put it in the trash.

7) If you an afford fresh mulch for your roses, do it ASAP.

One bactericide is copper spray. Another is Physan 20 (which doubles as a pruner sanitation solution). These are not easy on rose foliage. Both leave spots. Read the labels for adverse interactions with other sprays. It's a mine field.

In the season I had this, I ultimately lost very few roses. I sprayed in rotation: Fore, copper spray, Physan 20, Aliette and a targeted botrytis spray, Decree. The real cure didn't come until summer heat and drought.

Or maybe you don't have the same thing. If you see that it progresses to any beige spots on your canes...you might. If your roses are widely separated, all the better.

Here is a link that might be useful: Botrytis at Cornell

I cut the stem below the canker until I find healthy cane, to the bud union or soil line if necessary, for all but the smallest surface spots. Warm weather generally halts the spread of the canker that remains. This year there was less damage than usual, I guess because we had a mild winter and no spring freeze. I don't spray my roses, but stick to the more disease resistant and hardy roses for my area.

I have a couple of roses that get those little purple spots. They are also roses that are BS prone. I didn't do any dormant spraying this winter. I think its better when I do dormant spraying --- maybe I'll get more scientific about that.

Regular cane eating canker....just bite the bullet and cut it off. At least if you do that in the spring you have a chance at a healthy new cane. I try not to sentence my roses to struggling to maintain a damaged canes when they could use that energy for good canes, good leaves and lots of blooms. It was hard at first, this ruthless cutting out, especially when it was a big cane. Now it comes more easily.

For me, ownroot roses are less prone to canker. Teas tend to get it when they have happily leafed out and we get one of those quick nasty spring freezes. Certain "oh so delicate beauties" are also more prone - Moonsprite comes to mind. I keep working on that rose anyway, love the blooms and fragrance.

Thank you very much for all suggestions and resolutions. I am on my way outside. First I am taking shop vac and am going to literally vacuum all leaves. Than spraying. It's gonna be a big war.

Over Double Knock Out. Riiiggghhhtt.

The problem is that the Knock Outs are stupid. Major league stupid. They really have no idea that winter is something that shows up every year, and that smart roses prepare themselves. So getting blasted is going to be a regular occurance. Every year. Is this really what you planted it to do?

I should have never opened this thread (bad joke on my behalf). After reading through it, I had this gnawing feeling I knew what was going on with my "The Dark Lady", as she was the only rose in my garden who hadn't fully leafed out. In fact she seemed to have been struggling a lot, and the few leaves that did try and form, looked somewhat shaggy. Last year she was not only the first one to be full of leaves, but one of my first to bloom.

Upon a VERY close inspection my worst fear was confirmed. She had cankers. Quite a lot of them, too. :( :( So I filled a bucket half way with bleach, submersed my pruners, and carefully whacked her down (at least that's what she looks like now). There are about 5 canes remaining, but none of them have any remaining "swelling" buds that I could see.

After each cut I disinfected the pruners, and closely inspected her neighbors (Abraham Darby & Huntington Rose), and none of those 2 seem to have anything wrong with them.

Do you all think I've lost my Dark Lady? I LOVED that rose.

---
Wendy

Your Dark Lady will be a bit behind the other roses to bloom, but she can recover. Just treat her normally. She's got tens of dormant buds farther down on those canes, but now she's been shocked into awakening them.
That you cut the going-to-be-bad canes off now, rather than in midsummer was the right thing for the long term health of the rose.
And, yes, it isn't easy.

Thank you so much, Ann.

There is such a wealth of information here that I need a little time to absorb it.

Berndoodle, why would you leave your pruners in a disinfectant for 3 minutes? Why couldn't you just have a bucket of disinfectant, go swipe swipe, and move to the next cut? This is an honest question, and in no way am I being funny or sarcastic.

Thanks Ann. You have so much information, and again, I cannot even absorb it right now, but am happy to know that it is here.

Sammy

When I started to read this thread I kept thinking it was about cane borers. And why didn't people just coat the end of the cut canes with something.

Then I realized it was something else. Something I didn't have or at least so infrequent I never worried about it.

So then I got to thinking how come since it seemed to be a real problem for those posting. Then, you see this was a long mental process, I realized that I like Lynette never did the thick pine bark or whatever mulch. The only thick mulch I ever used was newspaper with grass clippings that by the end of summer was rumpled and tattered paper with dried or gone clippings. Which I removed at the end of summer as it was an unsightly mess.

So it seems there is something in all that mulch that harbors canker fungus. Could be??

Jim, I think what happens is the mulch traps moisture making conditions perfect for the canker spores to become active. This is the reason I no longer winter protect. If the rose cannot take winter, it has no place in my garden.

Barbara, who is no expert, but remembers reading that somewhere.

I am very greatful for this information even though it tells me that my latest patio pet, Geoff Hamilton, is going to get an amputation tomorrow. A nice fat cane putting out new leaves but definitely a sickly yellow with black. Bummer, bummer, bummer. What is worse is it looks like it is right down to the base too. Hopefully it gets arrested there and isn't going into the crown.