Knowledgebase

One entire stem of a perennial turned black #753180

Asked June 01, 2021, 8:13 AM EDT

Hi. I have a conefower or black eyed susan (sorry I don't know which this is) that had 1 stem out of 4 turn completely black. I have never seen anything like this before. Photo attached. No other plants (many near it) have been affected.

Carroll County Maryland

Expert Response

We cannot say for sure what is going on. We think this may be a type of root, crown, or stem rot. Possibilities may be southern blight, rhizoctonia, etc.   

https://extension.umd.edu/resource/root-crown-and-stem-rots-flowers

https://extension.umd.edu/resource/southern-blight-disease-flowers

Heavy soil and low areas that collect water will be more prone to root and crown rot problems. Check the drainage in the area and make sure it drains well. 

Cut the plant back and see if it puts out new growth. If not replace it.

Marian

Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 02, 2021, 10:47 AM EDT
Thanks. The really weird thing is just the one stem is black - the other 3 are fine (so far).

Appreciate the response. 

Dave

On Wed, Jun 2, 2021 at 10:47 AM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied June 02, 2021, 12:00 PM EDT

You are welcome.

Marian

Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 02, 2021, 12:25 PM EDT

Loading ...