Yes, I generally fertilize the PCIs around this time of year. Don't ask me with what, lol. Sometimes I use time release Osmocote Plus, sometimes I use 10-10-10, sometimes I use both!
So for our area (and you seem to be in the same climate zone), now, and then maybe again in the fall, like October sometime.
I still have to go plant out my latest PCI, but wet ground, rain, and appointments this week.
I'll try to get that done when I fertilize my PCIs, otherwise I'll just have to pot it up and put it in mostly shade somewhere.