Tall yellow flowers and red spots
Hi, What are the flowers and what is the red dots? I have these tall yellow flowers that self propagate. They have tubers for roots. They flower August and now are fading. Their leaves get red dots, turn brown and fall. I like the flowers which are easily pulled up in the spring after rain but I’d like to control the red stuff on the leaves.
Montgomery County Maryland
Hi - These look like Jeruselum artichokes (Helianthus tuberosus). The red dots are signs of rust, a fungal disease. This is typically a late-season disease that will cause some of the lower leaves to decline, but it is too late to treat it and we don't recommend using a fungicide at this time. Fungicides are not curative and will not clear up the existing symptoms. Rake up and discard the foliage and stems at the end of the season to reduce the fungal inoculum from the area. Here is more information. https://extension.umd.edu/hgic/topics/rust-flowers-and-vines
Hi Christa, I checked their root system which I thought was tuber since that is what they look like when their small in the spring. I was wrong- they’re not tubers. I posted pictures of the root system.
Jeruselum artichokes would probably have some tuber development starting by this time in the season. Since these do not, it is probably one of the other Helianthus species. There are many Helianthus species in Maryland that look similar. https://www.marylandbiodiversity.com/viewChecklist.php?genus=Helianthus