Hi
Description from Tomas Tamberg
"Iris pseudacorus hybrid BERLIN TIGER (Tamberg 1988)
An attractive hybrid, grown from spontaneous seed of HOLDEN CLOUGH x ?; strong growing plants produce stems with wide branching and many buds; the flowers show a strong and dense line pattern on yellow, creating a warm golden-brown colour effect; healthy, dark green leaves; in contradiction to first assumptions the variety grows better on a garden bed with sufficient humidity than directly in water; fertile, but yields only Iris pseudacorus seedlings; Award of Garden Merit RHS 1995

I grow several Versicolor x pseudacorus hybrid seedlings and they grow well along side Siberian Irises but do not like to dry out.Very Strong plants.
Tomas Tamberg would be the top Hybridiser for inter species iris crosses and his site is well worth the visit.

Here is a link that might be useful: Tomas Tamberg

I grow it.

A very easy to grow iris, and yes they are related to yellow flag, and are water lovers.

I think they are stunning.

pollyny, my garden has a lot of southern exposure - it gets kind of baked. Will berlin tiger bloom if I plant it in part shade instead, so that I can keep it's feet moist? Or would I be better off planting it in full sun, and just planting lots around it to shade the ground by it's roots and water it a lot?

What area are you in? In a southern state I would recommend a little shade. If you're in the north, full sun would be best, and keep it well watered.

If you would like I have a fact sheet on growing water loving irises. Email me through my website and I will email you a copy. My website is on my homepage.

I'm looking for this too as well as many of the species crosses that are in many colours. As well there are a group of Irises called Spuria that I'm looking for. The White w/ yellow and the all yellow forms are common here, I'm looking for modern hybrids in blues and other colours.