Just a suggestion, that you might want to have varying elevations rather than a long flat garden. Your herbs, especially the Mediterranean types will appreciate the better drainage from being elevated.
You might also hang pots off the 'brick fence' (do you mean 'wall'?)
If you have these evergreens behind the 'fence' you could begin trellising bignonia and cardinal flower vines and a Lady Banksia rose would appreciate something to climb up and through.
Much as I like iris and daylilies..their blooming times are short. Think about what you can find as an almost everbloomer that will thread through the iris and bloom after the iris have finished blooming.
Your hot afternoon spot will be great for all kinds of salvias which have a very long blooming period.
Just remember, they are perennial and they need their dead stalks to protect the roots so it can come up the next year.

Don't trim them back until all risk of frost is past in spring.

Hope that's not wild bermuda growing in that spot you want to plant.

blarkin,
Check out the soil. Is is orange? Is is brown and has a good texture, or is it sand?
You can spray Round up on it IF you want, and then dig out all the dead grasses, or you could just dig out all the grasses.
I would dig everything out when it is cooler, and buy fresh new soil and put that in it.
Then after planting whatever you want there, mulch it real good.
Just a thought, daylillies DO require regular watering in the hot weather, and so do iris.
So, after you plant them, buy a flat soaker hose and put it on the dirt BEFORE you apply the mulch, (under the mulch), then watering in the heat will be much easier.
I am very happy for you with your new home.
Enjoy your blooms next year.
Oh, by the way, go to HD and look for Fragrant Returns and Happy Returns in Dayliilies, they sell them in August.
They will bloom for you all summer, and the fragrant ones smell good.

--Thanks so much for your ideas! My sister has dug up over 300 iris plants to share with me! How long before I have to get them in the dirt? Can I store them until it is cooler and do the digging of the bed then?

Yes, I guess it is a brick wall. It's about 4 feet tall. I love the climbing roses idea!

I will check out the Happy Returns and Fragrant Returns for daylilies.

Any other ideas? You can see this long stretch from several rooms in our home, and I would love to have blooms going on all year long!

My sister told me about laying down plastic and killing the grass that way. Will that work?

Any ideas on how long I can store the newly dug up iris? If I can delay it a month or so, it will be much more comfortable outside and I would have additional time to design a nice plan.

It does look like it is bermuda grass. Fortunately, the area is bounded by driveway and the brick wall. The other side of the wall is all mulched and the big trees. Is bermuda grass difficult to get rid of?

trim down the iris tops to a couple inches and keep them in shallow trays with a bit of dirt. as long as you water them just a little they will keep like that for months. keep them on the dry side.