This is a Cistercian Abbey founded in 1137. They still hold services but there is also an association that runs a school for special-needs children and a service for the elderly on the grounds. For this reason, you must take a guided tour and are restricted as to where you may go. Photographs are allowed but not of people.
You go into the Gift Shop to book your tour. When we were there, the cost was 7.50 euro for adults and 5 euros for children. Check the web site for changes and schedules.
The abbey is lovely and peaceful as abbeys are. Combined with the gardens and lunch at the Garden Tea Room, it makes a lovely day out. Highly recommended.
The web site is in French but pretty self explanatory as far as times and cost.
We were there in early Spring on a very rainy day and toured the gardens under our umbrellas. Obviously, this is not the optimal way to visit Abbey gardens but it was lovely, many flowers were blooming and we did have a good time.
The gardens are a pleasant walk 200 meters down the road from the Abbey and have a separate gift store and also a lovely tea room overlooking the gardens. The gardens themselves are divided into six areas, the regular garden, the Rose Garden with the Valloires Garden Rose, the Cistercian Rose, and the Picardy Rose; the Islands Garden including the winter island, silver island, butterfly island; the Marsh Garden by a small canal and the Five Senses Garden where the plants are classified according to touch, smell, etc.; the Lamarck Garden which is an educational garden. The way it is set up, there is nearly always something blooming and the abbey is viewed as a backdrop in the distance. It is lovely.
In addition to the tea room where we had a delightful lunch, there are gardening supplies, souvenirs and tours available.
Spring: from 13 March to 30 April; 10am to 6pm (last entry into the gardens at 5pm)
Summer: from 1 May to 19 September; 10am to 7pm (last entry into the gardens at 6pm)
Autumn: from 20 September to 11 November 2010; 10am to 6pm (last entry into the gardens at 5pm)
If you're in the area (or even if you're not) go and visit these gardens. They're splendid, you don't know where to look first. It's really a place where you can recharge your batteries. Apparently they're only there since 1987.
There's also a shop where they have some nice things, and a restaurant (which was full when we were there). Entrance price for the gardens is 6,5 euro.
We didn't visit the abbey (I don't even know if you can visit it).