Sorry I have no great suggestions for your garden design but wanted to let you know I totally agree with your feelings about the iris borer. YUCK

I'm toying with the idea of two identical either buddleia (butterfly bush) or crepe myrtle, each pruned into an open tree form. Then, I'm thinking boxwood circles around the base. Really formal looking; I think it would be a good contrast to the otherwise "wildish" style of the rest of the garden. What do you think?

I like the idea of two identical things with the boxwood circles around the base. I think crepe myrtle may be a good choice for color and a more formal shape, but I also like buddleias - although they can get a bit overgrown and if you don't keep after them.

Hey Terri! Thanks! I'm open to suggestions as to modest sized shrubs/multistemmed trees. Crepe myrtle is just just hardy here and I do live in a cold spot, so not sure if I want to use them in something where, if they fail, it will be a big setback.

LysmachiaMoon said: I'm open to suggestions as to modest sized shrubs/multistemmed trees. .

My favorite shrub/tree is the juneberry (Amelanchier) , nice early white flowers and great berries for personal eating or wildlife and good fall color.

I like the idea of the formal look as long as you have the time and energy to keep it up
I get payed to trim way too many boxwood to even think of them in my gardens.

Cinda, thank you so much! This is a fantastic idea and guess what? My friend gave me about 6 of these little trees in big pots back in May and they've been sitting RIGHT THERE under the apple tree! They are probably small enough that I could plant three together to get the multiple trunks look. It just absolutely never occurred to me to use them!

That is a great choice! I wasn't familiar with juneberry or Amelanchier, so did a quick lookup. I actually have it natively in my woods but have always called it by one of its many common names - serviceberry. Never knew what the latin name was and never heard it called juneberry. I think it will work really well in shape and form. Another bonus - it is absolutely the very first tree that blooms in the spring - about two weeks before anything else for me. I heard folklore that the reason one of the common names is serviceberry is that it was an indicator in the early years of US settlement that when that tree blooms, the ground is thawed out enough to be able to bury people who had died over the winter.

Interesting it has so many names.
They ripen here in June , hence the name
My Mom calls them indianberries because the Indians use to pick and dry them , she remembers when she was little.

It's also called Shadblow because it blooms (blows) when the shad (a kind of salmon I think) start to run up the rivers in the Northeast.