Pour 12 tbsp. of oxygen bleach into a large plastic bucket. Oxygen bleach is powdered and provides the benefits of bleach without staining.
Pour 1 gallon of water into the bucket. Stir the ingredients well and pour the mixture into the reservoir of a plastic garden hose sprayer attachment.
Spray the affected area of ironwood with a healthy coating of the mixture.
Allow the oxygen bleach water to remain for 10 to 15 minutes. Scrub the affected area with a nylon scrub brush.
Remove the plastic sprayer attachment from the garden hose.
Rinse the oxygen bleach solution from the ironwood fence or ornamental piece with the garden hose.