I was browsing through the English Heritage magazine last night when I came across a photo of Bushy House Gardens. Now I know young Trisha visits Bushy Park a lot but she's never mentioned it.
I read a bit more and found it was publicizing the London Open Garden Squares Weekend. I believe the first one was in 1998 and it has been annual since 2003.
There are a number of squares in the city of London and they were built for people. Some of them are gated and locked and can only be used by residents of adjoining buildings. For the weekend some of them and other Lodnon gardens are open to the public. For instance I'm at a meeting in central London next Thursday and it's adjacent to Portman Square garden which is locked to riff raff like me! but will be open for the Open Garden Squares Weekend.
Unlike the Heritage Open Days weekend there is a cost but £7.50 in advance or £9 on the day covers the whole weekend. If you can get to 2 or 3 it may be worth it. Also I imagine some of the gardens will be free.
I'll have to look at the list and see if it's worth a trip up. A brief look seems to suggest it might be worthwhile. There are 200 Gardens signed up so far.
The London Open Garden Squares weekend is scheduled for the weekend of 12th and 13th June and curiously I am not on holiday!