flowerborders are so lovely
In July I took a break to France, and booked a gite in the countryside near to the Loire, and we were regularly dive bombed by house martins! I also recommend P and O Ferries for their accessible help on their new ferries, with lifts, and less queueing than eurotunnel. There were a number of chateaux within an hours drive, including Villandry and Chaumont sur le Loire. Some were very accessible.
The best had to be Villandry and also the Chaumont sur le Loire visit was brilliant. It has the International Garden Festival on for the summer months, with some brilliant garden designs.
If you are in a wheelchair there are some incredibly good deals, like free entry sometimes, which is always welcome. The actual chateux were limiting as to the floors you can visit, but the gardens are open and mostly accessible.
I thought the gardens were amazing everywhere in France, and particularly the wild meadows of grass flowers everywhere, but then I found the RHS the following month!