Q.Lantana Flowers Are Turning Black…never Had This Before.
Not much more to add…never had this problem til this year – plants were about 8 yrs old. I noticed one day this summer that a few of the flower bunches were turning black before they even bloomed. Not whole plant, just a couple of stems. But those stems that had black “balls” would eventually die even though leaves were green. At this point it has gotten bad enough that I’ve cut them all back. Not a water problem, can’t see any webs, small insects, etc. Sprayed with a soap solution, didn’t help. Can’t find anyone who knows or has had experience with this.
Certified GKH Gardening Expert
Unfortunately, this sounds like a case of root rot. You will have to have your soil tested to find out which you have. The usual suspects are Pythium, Phytophthora, Rhizoctonia, or Fusarium. Treatment will depend on which is in your soil.
Your local extension service can be of assistance with soil testing:
This collection of articles will offer more information on Lantana: