Ivor,
I am not aware of any way to import a list of what you have to your plant list in your profile. You are going to have to do it one at a time.
The easiest way is to go to the main Iris database page. In the "search" box start typing the name of the iris. The database will start a "suggested" list of results based on what you type. Pick the one that matches it and that will bring that cultivars page up. Down at the bottom of the page is the "add" button to add the cultivar to your list. I don't see an easier way to do it.
Greg
@islandview