I see a lot of what Daisy is saying, and I agree to some of it. From some of the pictures she showed, there's too much going on - too many of the same colour iris blooming to make the whole picture blind you fully, only allowing you to only what the colour of the iris is, or maybe the foliage with the plant. Personally, I am not the biggest fan of a huge clump of irises all the same colour. In my own garden, I'd absolutely select a few to stow away aside in their own bed because they're simply best on their own, or that they're gorgeous enough in a large clump like that to be as such.
I always put my iris types in a likely very disorganized fashion. A red, a pink, a white here. A yellow, a bitone, a plicata there. I like to spice up my placements with similar or contrasting blooms that make a good statement.
My garden is very messy (there's so many weeds that we couldn't keep up on, it has really taken a toll on our gardens), but there are large clusters of the same coloured irises blooming in the same area, but, they're not the only ones. Some bits of one particular bed might be very mix and matched, or messy, or all unanimous, pretty or....not so pretty. Luckily for me, all of what I have mixed together, or separated out looks great to me! What do you think? (Please ignore the bad state of these beds).
Here's a good mixture - Tan and purple/white noids
And some more mixtures!
One with a yellow noid introduced!
And one with mostly purple/white, but a stalk of a yellow noid, and a pink noid. (There were a few more pink that came up, but I couldn't catch them).
An...interesting mix between some lavender noids (Dalmatica??) and my tan noids from 2016 in a tire!
Here's some large clumps of mostly one colour!
Clumps of one with another cluster behind:
Some of my favourites of all groups!
Grouped:
Singles:
I even did some groups of two or three different varieties of my new iris types!
TBs Mariposa Autumn, Kind Candace, and Faithful and True together!
Lucy Doodle (IB?) and Deborah Dances (TB) together!
SDBs 'Cara' and 'Anne Lowe' together!
And TB noids that are pink/reddish bicolour and a yellow self!
An odd paring between the aforementioned noids of pink/reddish and the noid of yellow directly above, paired also with a noid I think is 'Gay Paree' around a pole.
Potentially 'Gay Paree?' (Either way, this iris is now around the pole with the aforementioned noids P/R and Yel)
That pole used to host some of my tan noids. Which really grew well.
And yes, I do also place irises of the same group/type together! My new lavender noids from a friend! (Dalmatica??)
I like a large group of the same to an extent, say four or five clumps together of just that, but my biggest preference is to say, take one rhizome of 'Beverly Sills,' place it down next to, or with 2-3 or even four other buddies that match enough of a feel to not be tacky, but be bold, yet graceful. Then again, I do like making some stark contrasts too! Who says I can't put a purple iris with an orange?
I guess it depends on your preference ~ I do like how some of what I've seen in this thread are arranged, and some, perhaps not as much.
I do not know what I think about the flat tops of irises...I am leaning more towards disliking them, unfortunately.
I have grown very accustomed to irises over the years, and know that the falls stick down in petals of three, and standards stick up in petals of three. Flares are...alright to me (some are really better with the flare sometimes!), but a flat top looks unnatural to me as if the standards all fell down because of disease, or rain or something of the sort. They're....odd. They differ so much from the norm that I see that I think it is making me lean towards disliking "flat tops" because they are so irregular to my "norm."
I do not know how I would feel if I had a flat top blooming in my yard, I could very well begin to love them just the same, but for now, I am not very fond of them, sadly.
Also, very much agree on Thornbird being a really...unnaturally good big clump blooming together. They're beautiful!