Is this canker?
Feiy (PNWZ8b/9a)
2 years ago
I have two roses that have this kind of purple stuff on the stems. In this photo, it's the main stem of Sweet Mademoiselle. The other rose is Firefighter which is even worse - all stems are surrounded by the same purple stuff(not sunburn). I noticed that last year and they seemed grow normally. In fact, Sweet Mademoiselle grew three times bigger than the previous year and reached 7' high. Because the infected area looked like spreading, I suspect it's canker but not sure. What do you think? Is it OK, or it's really a concern and the roses need to be removed?
Featured Answer
Comments (12)
Related Discussions
Help! Botryosphaeria Stem Canker (aka Blueberry Stem Canker)
Comments (2)In the attached link you can view a picture of the bark with a mottled red and green appearance (whatever the plants have looks a little different from plant to plant . . . perhaps different stages of disease). The attached below appears to be bubbling or boiling . . . it does not look healthy. Here is a link that might be useful: Blueberry Stem canker?...See MoreCanker or something else?
Comments (10)A few years ago a rose society friend had this on one of his climbers. He sent pieces of cane to the Michigan State University for a diagnosis. They explained to him that often times black spot spores will overwinter on the canes and cause this discoloration. It is not fatal and will disappear with warm weather. They recommended a spray with neem oil to kill the spores before they grew. Otherwise to just leave the canes alone until you see what you have to prune in the spring....See MoreFreeze damage or canker or does it matter?
Comments (3)Freeze damage is ruptured cells and they cease to function as cells for nutrient transport. Where Freeze damage happens, it is what it is. Canker is more, in a bad way. (At least this is what I believe based on growing a lot of roses inzone 6-7 where winter can be kind only to turn merciless in early spring.) Odd question, but important: are you colorblind? I ask because my husband is and there are reddish and reddish purple colors that he can't see. And that makes canker ID a whole lot harder.) Canker is a (IMO) catchall term for fungus that thrive on dead plant tissue. But worse, there are fungi that don't need a lot to get a mycelia-hold fast (little mycologist humor there) to appear on a stem. Are the fungi active? Apparently some, maybe most, give off ethylene gas in large enough amounts to affect adjacent otherwise healthy cells. When those cells are affected, the color changes from green to reddish magenta. And it doesn't change back, even when the causing fungus becomes inactive due to heat/humidity. I've seen Tea roses survive with only half a cane green an the rest dead . That cane will be weak but may last years, especially if supported. If you cut through a cane and see totally dead pith, then it becomes a learning experience: that pith will be crushed by the growth of the stem-unless the fungus has damaged the xylem and phloem system. I think there are major variations from rose class to class. I don't understand Chinas, aside from Old Blush. Polyanthas are like their kin, except most of the kinships aren't published. Hybrid Teas seem really susceptible to winter damages, and to spring damages. there's a reason they were greenhouse grown a century ago and where they would be budded on the rootstock of the countryside. If I were you, I'd choose to do autopsies on canes that you think are going to die and see what's happening inside them. I'd also check out some less healthy canes that you'd cut off anyway, and see if all the canes are looking fresh on the inside. And then some of us are going to have to watch out for cicadas this summer and that's a whole 'nother set of symptoms. Ann...See MoreCanker on Nectaplum?
Comments (7)Looks ok… cutting when branches are still small helps, but sometimes it can’t be avoided and it should still heal fine. The bark may have split because the new wood forming around the cut underneath the bark is pushing up from underneath, growing so fast, stretching it. Just a theory but I’ve seen it before and the trees were always fine. Good luck!...See MoreFeiy (PNWZ8b/9a)
2 years agoThanks you all. That's what I did last year - ignore it. It caught my attention because it not only didn't disappear but also spreaded more. I found an old thread on Houzz and someone there suggested it could be canker when it developed, so I ask it again. I apologize if the same topic annoys you. I think I'll "wait and see" again. I do hope it's only a cold damage.
This is another picture of SM. It showed the oldest stem has totally become purple (not woody), but it somehow produced several young stems last season.
BTW, rifis you're so funny! LOL
Feiy (PNWZ8b/9a)
2 years ago
oursteelers 8B PNW
2 years ago
Kristine LeGault 8a pnw
2 years ago
Related Stories
SIDE YARD IDEASNarrow Trees for Tight Garden Spaces
Boost interest in a side yard or another space-challenged area with the fragrance and color of these columnar trees
Full Story
GARDENING GUIDESSpring Citrus Care Reaps Months of Sweet Rewards
Learn how to tend citrus trees in spring and ways to preserve their delicious fruit
Full Story
WINTER GARDENINGPruning Secrets for Exquisite Roses
Encourage gorgeous blooms year after year with this time-tested advice on how to prune your rosebush in winter for health and shape
Full Story
GARDENING GUIDESGreat Design Plant: Eastern Redbud
With romantic pink blooms and heart-shape leaves, this ornamental tree has been inspiring affection since the days of the founding fathers
Full Story
MATERIALSWoodipedia: Walnut Wows in Traditional and Modern Settings
With its rich color and lustrous polished finish, walnut is a favorite wood for all kinds of millwork
Full Story
GARDENING GUIDESGreat Design Plant: Honey Locust Tree
No, it doesn't actually produce honey. But its dappled light and tolerant nature are treats in city and country settings alike
Full Story
PLANTING IDEASDesigning With Conifers: How to Unite Your Landscape
Create a landscape full of intrigue and artistry with the right placement of conifers and their supporting players
Full Story
GARDENING GUIDESGreat Design Plant: Corylus Americana Awakens the Woodland Garden
Plant American hazelnut for three seasons of interest and to feed our furry and feathered friends
Full Story
GARDENING GUIDESGreat Design Plant: Staphylea Trifolia Shines in the Shade
Plant American bladdernut for 3 seasons of interest: spring flowers and striped brown branches and bladder-like seedpods in fall and winter
Full Story
GARDENING GUIDESGreat Design Plant: Cornus Florida Benefits Wildlife
Flowering dogwood provides fiery red foliage in fall and beautiful springtime blooms
Full Story
Feiy (PNWZ8b/9a)Original Author