Wrought iron fences can rust when they are exposed to elements such as rain and humidity. While this is less of a problem in California than in some other states, it is still smart to take some steps to prevent damage. One way is to apply a protective coat of wax to your fence to help the starting of rust. If your wrought iron fence is near water like a pool or pond, rust is more likely to show up over time, so applying a protective wax sealant (which can be purchased at any hardware store) may be a great prevention.