There are invisible costs on not only our imported flowers but also conventionally grown local flowers. Another permie told me how imported flowers have to be treated (some with methyl bromide fumigation) prior to importation into Australia. An exhaustive list can be viewed here http://www.aqis.gov.au/icon32/asp/ex_QueryResults.asp?Commodity=flowers&Area=All+Countries&EndUse=All+End+Uses&QueryType=Search
Our conventional flowers are grown with artificial fertilizers and pesticides, but overseas they may be grown with chemicals which are banned in Australia, read more in the detailed article below.
More information in the Gardening Australia article http://www.abc.net.au/gardening/stories/s2739874.htm
Do we have an organic florist in the west? Feel free to comment.