I do not believe Iris siberica exists in a yellow form. I am not familiar with Louisiana Iris. But to me that looks like I. pseudacorus.

Thank you, floral. I got this in a gardenweb plant swap 20 years ago and lost its information long ago.,

Agree with Floral. Although there are several yellow I. siberica, none have that saturated tint (although the hybridizers are getting there). Some of them are gorgeous. But in any case, yours is I. pseudacorus.

I. siberica breeding has advanced by light years recently. Jan and Marty at Joe Pye Weed's Garden have done remarkable things with yellows. Some are inter-species hybrids, but many are pure I. siberica.

Yellow Siberian Iris at JPW's

EDIT: I have one of their earlier hybrids, 'Sunfisher'. They no longer list it in their catalog, but it's still miles ahead of most yellows, except for Jan and Marty's new ones, lol.

Thank you, fig! That's very interesting.

Thanks. I didn't know about the yellow sibericas.