Give your plants a shot at greatness with Bush Doctor Liquid Iron! Iron is essential to plant growth, playing a vital role in green up, energy production, and nitrogen fixation. Bush Doctor Liquid Iron is like a nutritional supplement for your plants, giving them a source of iron when they need it most. You wouldn"t train for a marathon without taking a nutritional supplement first, would you? For use on trees, shrubs, citrus and roses. OMRI Listed and Registered CDFA Organic Input Material.