Live things or semi-live things like plants and flowers are prime targets of confiscation at the port of entry of a foreign country. They do that to avoid importation of non-native pests.
Your best bet would be to send flowers through a local florist of repute, either through a wire transfer by calling the florist up, or online, if he or she has a secured website.
Actual bulk flower exports to foreign countries have strict packaging instructions, and often include an irradiation sterilization, at the port of entry of the consignment.
Someone would go to their florist in Phoenix (for example), pick out the arrangement and place the order for delivery to their friend in Fargo (where our store was located). We made up the arrangement and delivered it. The roses may have come in that morning from Utah on Amtrak, the orchids may have been picked up at the airport where they arrived from San Francisco. Other flowers may have come from local growers or our own greenhouse.
We duplicated the arrangement that the customer ordered in Phoenix and delivered it to their recipient hours later.
FTD works internationally in exactly the same way. The customer is billed in the currency of their credit card; the local florist is paid in their local currency; the recipient gets the arrangement selected made up at the local florist to whom the wire order was transferred. FTD has affiliates in most international markets and works the transaction seamlessly.