These vary in flowering behavior, same as other shrubs. If the foliage remains good-looking all summer lack of water probably not the problem. Maybe future results will be better.

Propagations of 'Royal Purple' I've bought and planted have seemed to lack vigor, wanted to be watered. Otherwise Smoke Bush should grow well here without coddling - as long as exposure is sunny, soil is well-drained and not infested with Verticillium. Noted making up part of the continental climate scrub growing near the Great Wall, along with peach trees and lilacs. Perhaps the most impressive specimens I've seen have been in eastern WA.

Mine may be 'Royal Purple'; it's quite purple. Maybe I'll try more water next summer and see if that makes a difference. You might be impressed with the one at McComb Gardens if you are ever out in Sequim.

I'm thinking specifically of a green one in Walla Walla that measured 35' x 35' in 1993 (Van Pelt, Champion Trees of Washington State, 1996, University of Washington, Seattle). Jacobson, Trees of Seattle - Second Edition (2006) might list others of similar stature. I don't have my copy here where I am posting from at the moment.

Jacobson (2006) mentions one in Seattle 21' tall, nothing as big as I had earlier thought he might.

Besides, as we all know smoking is not conducive to wellness.

I concur on vert. It doesn't seem to kill them, but it troubles them. I pollarded mine this winter and it's coming back nice. I think you may want to do that. I like them more compact than giant and rangy. I don't water either of my 2.