You could get a bumblebee hive this week. I think they would stay in your area. A class C hive from Hydro-Gardens would be about $130 with shipping. You would need to protect the hive from rain.

By hand I've used a small water color brush. Apricots are easy to pollinate. But flowers on plums and pluot are so small and dense that it is hard going.

Here is a link that might be useful: Hydro-Gardens

When my plums bloom, there aren't any bees out. Not even the Mason Bees which I farm. I do however see small flies among the blossoms and I believe that they do a good deal of pollination. It makes sense since there are plenty of native North American early-blooming trees and shrubs that depend on insects for pollination. Honeybees are a recent immigrant, and Mason and Bumble Bees emerge too late. Although, there are thousands of other bee species that may have done the job in earlier times, but have been displaced by urbanization.

Hey bfree, I had to hand pollinate my satsuma plum with my late santa rosa last year, I used some sta rosa flowers since it had so many, this year how ever, satsuma opened its flowers all within 2 or 3 days, and my sta rosa just barely started, so... I may not have any, or many satsumas, we'll see. what part of california you in?

Raffy