Don’s Expert Answers: Leaves turning black

Question From:
Jan Vedova in Wannanup, Mandurah Western Australia

Nature of problem:
Leaves turning black

Type of Plant (if known):

Symptoms of Plant Illness (please try NOT to diagnose your problems yourself):
Plants are mature leaves come out yellow, slowly turn green then start to go black and wither

Soil Type (e.g. sandy, clay or loam) OR Potting Mix Type:

How often do you water the plant:
Once a week

How many hours of sunlight does the plant get each day:
12 hours, but get wind too as by the beach

How long since you planted it:
Four years approx

Have you fertilised? If so, with what and when:
Gave them slow release fertiliser for natives but not regular

Is the plant indoors or outdoors:

Is the plant in a pot or in the ground:

What other treatments have you given the plant:

Upload photo if available:

Other Comments:
Most of them are grown next to limestone wall also have a couple in large pots.

Thank you for your help


Hi Jan, I just don’t know what your problem is caused by. Are all of your plants, both in pots and in the ground looking much the same? If so, it could be some form of toxicity: maybe bindii spray? or Roundup sprayed nearby? Dig a hole to see if somehow the soil is flooded?? If not, all that I can suggest is that you add Saturaid to the soil around them and then put a sprinkler on them, and water the hell out of them; ie 45 minutes daily for a week. Maybe take several soil samples along to your local nursery or Bunnings to see if they will do a soil acidity (pH) test for you. Maybe the soils are way too alkaline for them. Good luck, Don