Philadelphus maculatus (previously as P. madrensis

This plant smells so good in flower that it should be illegal or barring that, taxable. This could help with budget shortfalls because it is frankly addictive. One sniff and the response is "Ooh! Do you have this for sale?" Southwest native remarkable hardy with grape koolaid fragrant white flowers in masses. 

A note on identity: This and other pink blotched small-leaved Philadelphus with an effusive odor are likely P. maculatus despite their having been widely distributed as P. madrensis by us and others in the past