Hello Jklas, I find my plumerias though they love the heat, they also must get frequent, daily watering here. Liberally giving them like a power wash everyday all over before the hot sun comes around. I tend to get my blooms when it is going towards late Summer to Fall.
Looking at the plumerias in the photo, the media looks too heavy and dry. Try to improve that media, by adding more pumice. That way you can liberally water it everyday, and not worry too about root rot.
It really is a tough area to grow Plumerias here. Stockton is about 20 miles to our northeast and I find temperatures there are significantly hotter than ours, like 10 degrees hotter and equally much drier. With the very dry heat, it really takes a toll on any tropical succulent, or it may survive but hardly manage to bloom due to the very lousy humidity. The Plumeria your parents have originated in Hawaii, quite the humid hot area, vs. the dry hot area here. Inland conditions are always tough. You are in Ventura county so you maybe nearer the coast, so you get better ocean influence compared to the inland valley location of San Joaquin county.
