The Greenhouses at Roger Williams Park is a very nice place to take photographs, however it has been recently learned that there are some restrictions. A PSRI photographer recently found out that a permit is required for professional photographers bringing clients into the greenhouses to photograph. The permit needs to be requested way in advance to the actual shoot. Not only do you need the permit, but it will cost $150 per hour for family and engagement photos and $300 an hour for wedding photographers.
If you are just going to take pictures of the variety of plants in the greenhouse, a permit is not needed. The only fee is the entrance fee which was $3 for adults and $1 for children over 5 years old. According to the attendant at the ticket booth, tripods are allowed. Online information is limited, see the official site.