Oleanders Under Attack
Tough, waterwise and carefree oleanders all around the county are falling victim to an incurable bacterial disease. Oleander leaf scorch, which blocks nutrients and water flow from the roots to the leaves, is spread by the same glassy winged sharp shooter that carries the grape-vine killing Pierce's disease. Leaves on infected plants turn yellow and die, a process accelerated by hot, dry weather. Affected branches can be pruned out, but doing so will not save the plant. Gardeners forced to replace dead or dying oleanders used as hedges or screens might consider purple hop bush (Dodonaea viscose ‘Purpurea'), lavender starflower (Grewia occidentalis), or ‘Long John' Grevillea). Replanting oleanders again is not recommended since the new plants may be felled by the same disease. More information is at the Pest Note "Oleander Leaf Scorch" at www.ipm.ucdavis.edu.