Oleander Leaf Scorch in Phoenix

Beginning stages of OLS

Progression of OLS

Progression of OLS

Progression of OLS

Advancing OLS

 

 

 

 If you have oleanders, take a minute to see if they have Oleander Leaf Scorch (OLS).  OLS is caused by a bacteria (Xylella fastidiosa), carried by the leafhopper species, which has been decimating oleanders throughout the Southwest. 

The insects block the flow of xylem (ie, water) within the plant causing leaves to turn yellow, brown, and then to die off.  It looks kind of like drought-stress, except that the yellowing starts on the leaf margins and works its way inward.  If watering the plant doesn’t help, then it’s probably OLS.  The symptoms become more pronounced as the weather warms, affecting both red- and white-flowered oleanders. 

The only cure for OLS is to remove them completely.  Cutting them down to the ground will result in seemingly healthy offshoots and may delay the need to remove them by one to five years.  But they will ultimately need to come out.  Read more about Oleander Leaf Scorch. 

The good news is that there are very good, low-water, and non-toxic alternatives to oleanders.  Hop Bush (Dodonaea viscosa) does really well in Phoenix.  While its flowers are not as showy as the oleander, it is an evergreen that can grow to 10-12′ for privacy.

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