SoCal advice - decomposed granite

[foo dog]

I'm thinking if you get an auger and dig as deep as possible you may break through into a soil layer that has better drainage. Throw down some deep ferts and backfill the hole with a better soil. DC mixes well with decomposed organic matter but anything rich and loamy would be fine obviously. I always like to raise a bed too, if it's not too much trouble. just make a ring of rocks and fill her up with more soil. That sort of extra effort pretty much guarantees results.

 

[foo dog]

Yr plants are looking pretty good though