I don't know how well it fares in BC, but for hot climates, Vitex agnus castus is a great tree that resists drought once established, and displays violet flowers that the bees and other insects love. It can be pruned drastically when it gets too big, it will backbud on old wood. And it's easy to reproduce by cuttings, even with branches 1cm thick : just plant it in grow soil and keep it frost-free, the chances it will root are very high. I put my 'Hana matoi' next to it for the contrast : I should have planted my Hibiscus syriacus next to it, they flower at about the same time and have similar requirements. But it's already nearly 2 m. tall, so it's a bit difficult to move it now. It's also a cutting (about 15 cm long), taken in late February and that I took from a street plant that was on the other side of the street.
Vitex agnus-castus seems to do well around here, though I don't know if it's common in home gardens. I posted one at UBCBG in 2015 at August 19, 2015 - Blues. There were still some flowers on one I saw at Dart's Hill Garden in Surrey, BC (just south of Vancouver), last October.
While trying to make sure what I posted in English was correct, I saw that there are other colours, like pink.
