I read in a post here recently (couple weeks ago?) about yellow leaves on bougies being a sign of magnesium deficiency. Search back a couple of weeks. Someone recommended a Tablespoon of epsom salts (Magnesium Sulfate) mixed with the soil around the plant. There's an article out there somewhere if you google "yellow leaves bougainvillea" that ought to find it.

Thank you! :)

Louisa, the website won't let me comment on your new question about the soil. Don't worry, that's just mulch/woody debris rotting and breaking down. That's what it looks like when my mulch breaks down anyway - it forms kind of a mat over the soil.

Since the others are fine...that one's emitter might be clogged. She's not getting her fair share of the water.

Yeah, that's a good possibility Stan. I have found that mine need much more water, and are much less tolerant of the beating sun, as babies, than I would have expected.

Thanks, everyone. I've given that one lots of supplemental water, but obviously not enough. :( I'll check the emitter, but I think it's too late to revive this one. :(