I have a basil pesto perpetuo (a variegated variety of basil) I'm growing because it just looks and smells nice (not to eat). It supposedly likes sun (it's in a pot next to a window that gets plenty of afternoon sun) and lots of water. The soil is never-before-used potting soil. It's gotten a lot taller since I bought it.
However, many of its leaves are just falling off. If you breath on it hard, leaves fall off. Why isn't it doing well?