You can do that Louise...
Go to the Plants Database at the menu bar on top.
Then go to "Visit our plant-specific databases:" (Do not select "search all plants by characteristics"
Select Irises
Search by characteristics
I've found that selecting fewer choices yields better results.. also, one hybridize4r may see a color as "purple", while another may see that same color as "violet".. You just have to keep trying different choices... Sometimes I'll go to a similar Iris just to see how it is described, and start from there... Also search the Children and parents can sometime give success.. Good luck