Nick,
The bowl mentioned at the Getty is by Bob Irwin – an amazing artist and yes landscape designer (also did the DIA Beacon) and influential for many landscape architects. In San Diego, don’t miss the Salk and Neurosciences Institute just north in LaJolla.
In LA, also check out the Huntington Gardens – wow.
Hargreaves has several projects in the northern California area – Guadalupe River park in San Jose, Bixby Park, Candlestick etc. These have all undergone some degree of entropy – so understand that this is part of the intention of the designer.
The gardens around the DeYoung and Academy of Science museums in Golden Gate park are amazing, not to mention two amazing museums.
In the SF area, three are works by Halprin, Peter Walker, Andrea Cochran, Cheryl Barton, Walter Hood. If you can get up to wine country the Cornerstone Garden is at the south end of the valleys.
And of course the amazing natural landscape of the area. No one can design a redwood forest! Just sink in…!
MP