Irises that are introduced in the US are eligible for awards. So the Blyth (he's Australian, btw) irises that have won awards are those that were introduced by Keith Keppel in Oregon. The American Dykes Medal has an additional restriction in that the irises have to be hybridized in the USA as well as being introduced here.
As an example, Barry Blyth created Decadence
Tall Bearded Iris (Iris 'Decadence') in Australia and introduced it through Keith Keppel in 2004. It won numerous awards, including the Wister Medal (highest award for TBs), but it's not eligible for the Dykes Medal (unless they changed the rules recently?).
