For nineteen years here part of my organic landscaping business THE GARDEN DOCTOR in Tampa was organic lawn care of St. Augustine lawns. I'd add a few plugs of St. Augustine strains, apply just once seeds of mixed Bermuda strains in summer, each March I'd apply a COPIOUS amount of dolomitic limestone to benefit the grass and greatly suppress weeds, and apply organic soil foods four times per year. They LOOKED like a monoculture but were not. Here are pics of one I cared for on Davis Islands for nineteen years