FS go for ftd.com

Usually thess sites have agreement with flower shops in several cities in the country so maybe you can place the order now (I mean this week) and ask to have it delivered next week (by sept 6th) as your request. And for sure it will arrive in time.

Details on customer service

http://www.ftd.com/custserv/

link for contacting them

http://www.ftd.com/custserv/email.epl?orderinquiries&AID=orderinquiries&...

Regards!!

PS: any doubts on te service just contact them on email and ask to clarify all your queries.