This post is actually from 2 separate sites in Bay Co, FL. The very first site contains S. leucophylla and S. flava var. rugelii as well, and the second site is pure S. psittacina.
Unfortunately, both sites are the result of disturbed or altered land, so they are not the natural, pristine habitats that you see in many of the posts below. The good news is if no herbicide is ever sprayed, these plants will likely persist for a very long time.
This very first site is kept in check by an easement where no building is allowed. The grass also seems to be mowed frequently. I found a gigantic S. p