My guess is also Oleander, checked in the Exotica & confirmed it. Nerium oleander 'Album'. Also oleander is very poisonous if eaten, any part of the plant. I believe it is quite fragrant and beautiful and has been the subject of songs & books about being poisoned by it's beauty. ( and literally by eating it unsuspecting)
Your designer nust be on vacation down south because it thrives in hot, dry weather.