I'm amazed by the density of the flowers in this shot! Do they get some special food? Perhaps extra potassium/wood ashes? I understand that extra nitrogen produces the contrary effect. So I'm puzzled how to get mine to produce such a mass of flowers. Of course the photo is stunning and I melt over that navy blue!

Arturo

P.S. in the background there's a blurred backdrop of another SDBI bloom mass...

No--no special food
some compost initially when first planted, and then at some interval of years, but nothing regularly timed or special.

It's just what clumps of dwarfs do.

I was watching my Iris pumila seedlings and these also tend to spread into tight clumps. Last season, even my seedlings have shot up many blooms per clump. Perhaps that trait is what makes their hybrids, SDBIs , become so attractive! I simply can't wait to see what your seeds will provide eventually! Your explanation only has whetted my appetite for these petites even more! Good to know that no special treatment required! again.

Arturo