For the continuing gardens in art series, here's a sketch from the Huntington Conservatory. The Huntington is an amazing place: it's a library, an art museum, and it has beautiful gardens. If you are ever in Southern CA, you ought to check it out. Just a warning, there's more to see in each of the areas than you can really see in a day - but it is good fun.
The sketch above is taken from the website, which sadly doesn't have a great set of photos its fourteen different gardens - although there are some nice macro flower photos in each of it's garden sites. It is also worth a poke around the art collection, lots to see there. The library section has photos of its treasured pieces.