Diagnosing Yellow Leaves on Chinese Star Jasmine in Western Australia

Selective yellowing on a few Chinese star jasmine plants among healthy neighbors points to localized soil conditions rather than systemic issues.

Iron Chlorosis: The Prime Suspect

Interveinal yellowing (green veins, yellow tissue) on new growth typically indicates iron deficiency, often caused by alkaline soil pH locking up available iron. Even within a small planting area, soil pH can vary significantly due to construction debris, limestone leaching, or irrigation water chemistry.

Confirmation and Treatment

Rule out overwatering first—saturated soils also cause yellowing but affect entire plants uniformly. If drainage is adequate and only 3 of 10 plants show symptoms, apply chelated iron (iron sulfate or EDDHA chelate) to the affected plants' root zones. Follow package rates conservatively; over-application causes toxicity.

Long-Term Management

Test soil pH around affected vs. healthy plants. If alkaline (above 7.0), incorporate elemental sulfur or acidifying fertilizers to gradually lower pH. Mulch with pine bark or needles to maintain acidity. Ensure consistent moisture—drought stress exacerbates nutrient uptake issues.

Chinese star jasmine thrives in your Mediterranean-like climate; correcting soil chemistry will restore vigorous, deep-green growth.