For beginner gardeners, a simple reliable petunia is the best choice to grow for long summer color. Experienced gardeners might argue these zone 9-11 annuals are trite. They’re available at every nursery and hardware store, bursting in bright colors, begging loudly to be taken home. Still, they cheer up a garden like no other flower. I’ve been a professional gardener for over a decade and a half and every year I use them in arrangements, both for myself and clients. What Kind Is Best? Because both commercial businesses and home…