Don’s Expert Answers: Slow growth and leaf discolouration/spotting/dropping

Question From:
in Herne Hill , Geelong Victoria

Nature of problem:
Slow growth and leaf discolouration/spotting/dropping

Type of Plant (if known):
Teddy Bear Magnolia

Symptoms of Plant Illness (please try NOT to diagnose your problems yourself):
Leaves no longer shiny and dark green. Leaves have black spotty outer area which over time spreads over entire leaf, they then drop.Limbs bare of growth due to leaf drop.

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

How often do you water the plant:
Twice a week

How many hours of sunlight does the plant get each day:
Full day sun

How long since you planted it:
1 1/2 years

Have you fertilised? If so, with what and when:
Slow release fertiliser pellets every spring, Seasol every few weeks and heavily mulched in sugarcane mulch

Is the plant indoors or outdoors:

Is the plant in a pot or in the ground:

What other treatments have you given the plant:
Nothing else

Upload photo if available:

Other Comments:
Some leaves don’t have the ‘spot’ but they are a VERY light green colour often going a rusty yellow hue through the center of the leaf. The plant is quite gangly looking with completely bare limbs? One area I haven’t investigated yet, is soil PH levels …
Any advice or observations would be very appreciated, this is most frustrating as Magnolia’s grow well in our suburb- just not our garden!
Many thanks Suzane

Hi Suzane, My best guess is that the problem is in the soil. My guess is that the clay soil is compacted and/or the water isn’t getting in OR it is flooding the poor plant. Your plant is winding down to die. I guess that the underside of the leaves have been covered with mites, hence the discolouration on top of the leaves. The mites are only there drinking the plant’s sap because the poor plant’s immune system is failing due to root dieback. I would dig it up and move it to a better area where the soil is fluffy and healthy. Use a wetting agent as well. Percentage chance of recovery: 10%. Good luck, Don