Yellowing of plant leaves caused by insufficient chlorophyll. Often indicates nutrient deficiency (particularly iron, magnesium, or nitrogen), waterlogging, or root damage. Interveinal chlorosis (veins remain green) typically indicates iron deficiency.
Chlorosis manifests as yellowing of leaves whilst veins often remain green, indicating the plant cannot produce enough chlorophyll for photosynthesis. In Australian gardens, this condition is frequently caused by iron deficiency in alkaline soils, particularly common in limestone-rich regions. Magnesium and nitrogen deficiencies also trigger chlorosis, especially in acid soils of tropical and subtropical zones.
Different causes require different solutions. Iron chlorosis responds well to chelated iron products available at Bunnings, applied as soil drenches or foliar sprays during spring and autumn. Nitrogen deficiency calls for application of a balanced fertiliser or organic alternatives like blood and bone. Check your soil pH with a testing kit—most plants prefer slightly acidic conditions (pH 6.0-7.0). In heavy clay soils prone to waterlogging, improve drainage by adding compost or raising garden beds.
Climate significantly affects chlorosis risk. Alkaline soils in dry inland regions are particularly prone to iron-induced chlorosis. In tropical zones, heavy rainfall can leach nutrients, causing deficiencies. Address chlorosis promptly, as affected plants photosynthesize inefficiently and become stressed. Preventative measures include mulching with organic matter to regulate soil conditions and regular soil testing. Most Australian plants respond quickly to corrective treatment within 4-6 weeks.