I've actually called florists in Poland and had excellent results. If you can, get a florist located in a hotel as they always have somebody around who can speak English.
Why??? Look online for a local flower shop in Warsaw and order from there. I do it for many years already, have my favorite flowershop in Gdansk. They do an awesome work and much cheaper than international delivery. You can discuss the current store stock with the owner, make suggestions about the arrangement, the delivery etc. You pretty much would know what are you ordering.
If you want to send flowers to Wroclaw use only this URL: akant.wroclaw.pl (copy & paste in your browser address bar) - the online and local street flower shop. They deliver in Wroclaw and you can order flowers online.
With no middleman you save a lot and you get real bouquet - like on the picture.