So Iris ensata Sue Jo is one of my new cultivars, flowering this year for the first time. It was bred by Donald Delmez, and was registered in 2003. It is a double flower with flattish ruffled, flared petals which have striking blue veining on a white background, with yellow signals. This year it had a flower head of about 5 inches across, and grew to about 20 inches; it can grow up to 39 inches. The style arms are a dark blue/purple and are slightly ruffled on my plant. It has received several awards including an Honourable mention in 2006, Award of merit 2008 , and the prestigious Payne medal in 2010. It is a striking plant, which I think will form an impressive clump over time.
Currently this plant is in a raised bed in the side garden where it seems quite happy. Unfortunately, a neighbouring Lupin is crowding it out a bit, so some re-arrangements will have to be made in the Autumn (Fall). Iris ensata are greedy feeders and like plenty of sun and water, so if your garden is designed to show off their ephemeral beauty, then you have plan around those considerations. So, aggressive perennials have to be located at a suitable distance, and a strategic use of annuals planned to fill in the gaps when these lovelies have finished flowering.
In my old age I am embracing quite a vulgar taste for colour (very Non -U q.v). So the green foliage of Iris ensata, whilst quite lovely, does not satisfy my requirement of continuous colour and interest in the garden. This year, I have relied on Cosmos 'Sonata' to fill the gaps, which have certainly ticked the box as far as colour is concerned. However, these are quite big plants requiring quite a bit of space, and a lot of watering. I suspect they are competing with the Iris ensata for both nutrients and water. The other good value 'annual' (seems to be perennial in my garden) is Nicotiana mutabilis, which has airy pink fronds of white flowers, which turn pink after pollination. Unlike the stately Nicotiana sylvestris, N. Mutabilis appears to have no discernible scent. Again, it maybe a to much of a greedy feeder to continue using it in subsequent years.
More research and planning to be done!