Rose Diseases: Stem Canker
This is a fungus caused by open lesions or cuts on your plants. It will mostly occur on canes and stems. These wounds can happen in many ways.
Bad pruning or trimming can easily leave your roses susceptible. Allowing the canes to rub on each other cross wise
can also cause friction wounds. Be sure to give proper spacing for your roses.
Here are the three types:
Coniothrium fuckelii - Common, symptoms of dried up legions
Cryptosporella umbrina - Most common but most noticeable
Coniothyrium wernsdorffiae - most difficult to treat
There are different stages to this fungus. In the beginning, they are only small red/yellow spots on the cane. Over the winter in some colder zones, they may initially show as black, but will turn to red/yellow once the cold protection is removed. Thes red/yellow spots will then spread and potentially circle the branch, changing to a brown color. If it is allowed to surround the whole cane, it can kill of growth entirely. Its best to nail this one early if you can.
To prevent stem canker, keep in mind the following:
- Use good pruning techniques. Leaving open wounds on the cane will increase the chance of fungus.
- Plant roses at an appropriate distance from each other. Do not allow the stems and canes to cross or rub each other.
- Remove dead and dying wood and canes promptly.
- You can use a fungicide that treats black spot to treat this as well. As with all fungicides, use with caution.
Pages Related to Caring For Roses
Browse our pages on rose care. From basic planting techniques to advanced budding and propogating, we've got something for everyone.
Care Of Roses
Start at the beginning, and get an overview of what's involved with growing roses.
Doing a poor job with your plant can leave it with weak roots. Make sure to get it done right.
Sometimes your blooms need a trim so they can have room to sprout and re-grow.
If you want continuous blooms through summer, then you need to deadhead your roses.
A vase full of vibrant bloomers looks great in the dining room. Learn how to do it yourself.
A little more advanced, but see how you can easily increase your stock of roses.
Make sure that your roses can survive the winter and come back even stronger in the spring.
Some of the common rose diseases like blackspot, and how to get them under control.
Common bugs and insects to look out for on your roses, and what to do about them.
How to use the state of the leaves to check plant health on a rose bush.