If you are growing your Gardenia as a potted plant indoors, keep it out of direct, hot sun, and allow it to only get bright light. I think that your 'black mold' is more than likely an algae growth, which is a cosmetic problem for your plant rather than a health problem.
Monona is a city in Dane County, Wisconsin, United States. The population was 7,533 at the 2010 census. It is completely surrounded by Madison and is part of the Madison Metropolitan Statistical Area.
The city of Greek Lake is located in Green Lake County and is home to 1,100 residents. It is know for it's fishing and recreational tourism, boasting camping, biking, multiple golf courses and more. The lake has 27 miles of shoreline, with a depth of 230+ feet making it the deepest inland lake in Wisconsin.