How to Fertilize a Barberry
- 1). Collect soil and have it tested to determine the current pH and nutrient levels.
- 2). Spread mulch around the barberry to prevent weeds and quick changes in soil temperature.
- 3). Apply a light dose of the general-purpose fertilizer following the manufacturer's instructions in early spring before new leaves start to grow. Apply at a rate of 1 oz. per 3 to 5 gallons of water spread over 100 square feet. Barberry does not require much fertilizer, and you may not need to fertilize it every year.