Perennial suggestion for Zone 7A

[csdude55]

Using perennials that I already had on hand, I've set up several part-sun sections (and one full-sun section) that stagger in height, and I tried to set up bulb plants so that when one dies down another one blooms.

So my pattern is:

Purple Heart (the lowest)
Hostas
Autumn Joy sedum
Bulbs (Easter lilies, irises, and day lilies, all planted near one another)

And then behind those I either have Devil's Trumpet (in a container), calla lilies (in a container), or hydrangeas (in the ground).

I have a ton of excess Anne Marie ivy that I'm thinking about adding as ground cover, but haven't decided yet.

I feel like I'm missing something, though, between the sedum and the bulb plants. I'm trying to think both short-term and long-term (I'm about to refinance my house so I need a good appraisal, but I want everything to grow in together for next year, too).

Can you guys suggest an appropriately sized perennial that might help balance it out?

Phlox would look great this year, but it would likely come back too big and outgrow my irises. Vinca major (periwinkle) is my next thought (at an 18" height), but it's kind of pricy at about $2 each root (and I would easily need 50 of them). Vinca minor is much cheaper ($20 for 50), but with a 6" height it's too small. Coral Bells, maybe?

 

[JBtheExplorer]

One of my favorite plants is Stout Blue-eyed Grass. It gets around 12" tall at most. You could buy seed, scatter it in winter, and they would start growing next year. It's not actually a grass. It's technically in the Iris family, but the flowers do not resemble Iris flowers in the traditional sense. Blooms May, June, and just barely into July in my area.

I worked on establishing a row along the outer edge of my pond and now it looks amazing! So many flowers!

Another plant great plant is Prairie Smoke. Flowers get to a height around 12" to 18". It gets little pink flowers that point downward. When pollinated, they'll face upward and grow "troll hair". It starts growing and forming buds right as the snow melts. Blooms April, May, June in my area.

 

[csdude55]

Those are both gorgeous! I don't think I've seen either of them locally, but I googled and they're both OK for my zone so I'm gonna have to go look for them at some local nurseries.

It stopped raining earlier today, so I got some pics of my main area around the pond. I had 3 HUGE hostas that I split in to 20, but I did all of this late-May to mid-June so it was a little late and nothing looks... great. I'm hoping it will all fill in better next Spring. But you can see that I have more empty space between everything than I think I should.

I haven't mulched this area yet, I was hoping to figure out what to fill in first. I have this one Coral Bells plant that I could split in to 4 small rhizomes, but they would all be tiny so I'm not sure how long that would take to look good... probably 3 or 4 years :-(