Gnarly stems on marigolds - Ask Extension
I have noticed a growing problem with my marigolds having rough, twisted and knobby stems Is it a disease that is transferred to other marigolds? I...
Knowledgebase
Gnarly stems on marigolds #893875
Asked March 08, 2025, 10:09 AM EST
I have noticed a growing problem with my marigolds having rough, twisted and knobby stems Is it a disease that is transferred to other marigolds? I have had marigolds as borders in my garden for decades and usually start them from the past year's seeds plus new ones. This problem showed up 2years ago and returned again this past year with even more plants. I remove the plants when it appears and do not save those seeds. I toss plant in trash. The flowers don't seem to be affected but plant is dwarfed.
Ramsey County Minnesota
Expert Response
From an Extension source:
It sounds like your marigolds may be suffering from a virus or herbicide exposure. Twisted and knobby stems are common symptoms of these issues. If you haven't used any herbicides on your property, it is still possible for the plants to be affected by "herbicide drift" from nearby areas where these chemicals are used. Additionally, some viruses can cause similar symptoms, but if your plants don’t show other clear indicators of a virus (such as unusual leaf coloration), then herbicide exposure could be a more likely cause [2, 3].
Since you’re experiencing this problem consistently over the last few years, it may be worthwhile to consider growing different varieties or species of flowers that are less susceptible to these issues, especially if the marigolds are being affected by a persistent virus or environmental conditions. Unfortunately, as the management of viral diseases and herbicide exposure can be challenging, there isn't a lot that can be done to correct the damage once it's occurred, apart from ensuring good care practices such as adequate watering and perhaps controlling nearby herbicide applications [1, 2].
If you are concerned about potential disease transmission to other plants in your garden, it's crucial to continue removing affected plants and not saving seeds from those. This may help minimize the risk of spreading any pathogens. Consider also checking with local authorities or extension services to explore further options for managing this issue in your area.
General information
https://apps.extension.umn.edu/garden/diagnose/plant/annualperennial/marigold/leavesblotchesorspots.html
It sounds like your marigolds may be suffering from a virus or herbicide exposure. Twisted and knobby stems are common symptoms of these issues. If you haven't used any herbicides on your property, it is still possible for the plants to be affected by "herbicide drift" from nearby areas where these chemicals are used. Additionally, some viruses can cause similar symptoms, but if your plants don’t show other clear indicators of a virus (such as unusual leaf coloration), then herbicide exposure could be a more likely cause [2, 3].
Since you’re experiencing this problem consistently over the last few years, it may be worthwhile to consider growing different varieties or species of flowers that are less susceptible to these issues, especially if the marigolds are being affected by a persistent virus or environmental conditions. Unfortunately, as the management of viral diseases and herbicide exposure can be challenging, there isn't a lot that can be done to correct the damage once it's occurred, apart from ensuring good care practices such as adequate watering and perhaps controlling nearby herbicide applications [1, 2].
If you are concerned about potential disease transmission to other plants in your garden, it's crucial to continue removing affected plants and not saving seeds from those. This may help minimize the risk of spreading any pathogens. Consider also checking with local authorities or extension services to explore further options for managing this issue in your area.
General information
https://apps.extension.umn.edu/garden/diagnose/plant/annualperennial/marigold/leavesblotchesorspots.html
