Are My Dandelions Diseased?

Asked April 10, 2016, 9:29 PM EDT

We're finding a lot of dandelions in our yard with deformities, several fasciated and now many with these bumps all over the stems. What is causing this and should I be concerned about the rest of my garden (other flowers and vegetables)?

Clark County Washington

6 Responses

Thanks for the fasciated dandelion photos. Dandelion fasciation also known as cresting occurs when a growing point on the plant changes from a round dome of cells into a crescent shape. It could be caused by several events such as homone imbalance, infection (virus, bacteria or phytoplasmas) extreme weather changes, mechanical changes by garden hoe or even feeding by insects or other animals. Typically the exact cause for a particular incident is unknown and often appears randomly.

Are the stem bumps on new dandelion growth? Do they develop further mutation? Review of other fasciated dandelion research did not mention the type of stem bumps in your photo, nor were the bumps documented as a dandelion problem. Possibly, if you are curious, you could monitor the plants growth.

Fasciation has been documented in numerous other plants (including ferns, woody plants, annuals and perennials). Your fasciated dandelions do not pose a threat to other garden plants. You could removed the fasciated dandelions or you could leave them alone as causes no harm and eventually the fasciated dandelion may get overshadowed or suppressed by more vigorous shoots.

Thank you so much for your info! Pardon me for not being more clear about the stem bumps. They do not appear so far on the fasciated dandelions, but the flowers that do have them are all twice as tall as normal dandelions, and the affected dandelions are growing close together in clusters. My daughter dissected one stem and they do look like solid growths. I hope this description is more helpful. Thank you!

The dandelion stem growth you describe is not thus far mentioned in research materials. It could also be a growth pattern change similar to fasciated dandelion. But available dandelion information does not offer a diffinitive answer. It is certainly a curious dandelion growth pattern and locating a better answer for you requires further inquiry.

Ok, thank you so much for taking the time to look into and answer my questions, I really do appreciate it!

Just some follow up photos of the growths if you're interested. They are now spreading to the leaves and look like tumors, and many of the affected dandelions are becoming curled.

Thanks for the follow-up dandelion photos. These stems are quite different from the fasciated growths submitted earlier.