Nutrient Problems: the majority of the Australian plants, growing in our gardens, get by with a minimum of care and attention. After planting they are mulched and watered regularly for the first two growing seasons. Regular pruning is also undertaken.
A few Banksias and Grevilleas need slightly more attention. Some of these members of the Proteaceae family develop yellow foliage. An iron deficiency is blamed for this unsightly condition. Itís our opinion that iron deficiency may be allied to other nutrient problems that leads to yellow foliage. The suggested treatment is to water the plant with an iron chelate solution. Unfortunately we have killed more plants than we have cured using this treatment.
Our solution (pun intended) is to water with a soluble fertiliser. This treatment restores plants to full, green-foliaged health. Plants may have to treated two or three times to cure the problem. The plant is cured when new foliage appears with a healthy green colour.
The soluble fertiliser must contain all the trace elements or micronutrients including iron. In
Australia, Aquasol and Thrive are two soluble fertilisers meet these requirements. We use either brand. Two measuring spoonfuls dissolved in ten litres of water is the strength we apply.
Yellow plants are thoroughly watered with the solution. The image shows a Grevillea Ivanhoe. The lower, older leaves are yellow and the upper, younger leaves are green. This plant was treated three times over a period of four weeks to cure the yellow foliage condition.