Our Sulphate of Iron 1.5kg is a plant food tonic for ericaceous (lime-hating) plants such as heathers, azaleas, rhododendrons and camellias. It can be used on any soil to correct iron deficiencies, which cause leaf yellowing on roses, shrubs and ericaceous plants. It contains fast-acting iron for strong growth and rich green foliage. And to help prevent leaf yellowing (chlorosis). Apply directly onto the soil during the growing season (March to September).