I don't know whether someone else has already commented on this elsewhere. I have a mature R. moschata, planted around 2010 and left to grow. Once it got going, which took a few years, it went up and up, getting support as it got larger as its growth is lax, and has now reached the dimensions of a moderate climber. It has never gotten much pruning, just occasional light removal of aged growth, and has never been cut back hard in its life, but it blooms the latest of all my roses. This year it came into flower this month, July, and I think that's usual. (In comparison, this year the Teas began flowering in April, and the once-blooming roses, Gallicas and Co., in May.) It does well in our climate in the Italian hills, with mild temperatures, summer heat and drought, good annual water, historically around one meter annually, though recent years may be drier. It gets no supplementary water and blooms well nonetheless.
A couple of comments about the observations in 'The Compleat Florist': hard pruning at the right time of year likely would keep the plant shrubby, and also likely cause the plant to require more water for regrowth. My unpruned plant blooms tolerably well, but I'm not fussy about these things. Also, my plant, own root, has not so far suckered out.