3D garden designs

[Cogcog]

Anybody recommend software or a web site where I can do a bit of 3D design?

I have used the BBC version but except for grass and a few non-descript trees, beyond that it gets very limited.

[zaphod42]

Floorpoanner.com is free for the first few designs, allows 2d and 3d. Does gardens as well as floors
Not amazing, but not bad.