These are groups and organisations which do gardening/horticulture in the local area. I have also added bigger groups that are gardening/horticulturally based as it made more sense to place them here.
Growing Hollingdean is a local ecological group that has helped create multiple community gardens around the city. They hold community events like seed swaps and plant fairs. They also have volunteering days at many of the gardens as well as tree guardians.