Identify Siberian Iris - white with yellow
I have been growing a lovely iris (white with yellow splotch on throat of petals) for about 15 years. I don't know the name - it doesn't look like photos I've seen of Butter and Sugar but it looks very much like one in a photo I found on a gardening website. It was identified only as 'white iris' - photo from New York Botanical Garden. It is the second photo on the page about half way down.
Does anyone grow this iris?
Thanks for any information you can provide.
Here is a link that might be useful: Daily Apple blog