Plant Health Problems
See Perennials for a detailed discussion of problems that may occur and are common to most herbaceous ornamentals.
Diseases caused by Phytoplasmas:
Aster yellows, phytoplasma.
The pathogen is a prokaryotic organism without cell walls. It infects the phloem of susceptible plants and causes a general yellowing and dwarfing symptom. The phytoplasma is spread by a leafhopper vector.
Infected plants should be removed and destroyed. Early season control of the leafhopper vector and removal of weed hosts may help prevent re-infection.