Answer: Iron oxide should not affect your barberries. I wonder if they are getting enough or maybe too much water? Barberries need a deep soaking once or twice a week (twice in the summer time), but the soil needs to drain well between waterings. I suspect your soil is on the clayey side. If so, it will hold lots of water, even if the soil surface appears dry. Try digging down a few inches to check the soil moisture a few days after watering your plants. This will give you an idea of how often to water. Good luck with your barberries!
Q&A Library Searching Tips