I don't like the phrase, it sounds wrong to me. But then on reflection I realized that while I would say "I am growing lazy." I don't say "I am growing sweet peas." I tend to say that I planted them or I have them or they are growing in my garden (planters actually.) I provide what they need but I don't cause them to grow. So growing a business makes more sense than growing plants since it is not a natural process.
Hmmm, I seem to have convinced myself tother way round from whence I started.