What are the trees there? Some trees make it impossible to grow much. The area seems much too small for the huge variety in the two suggestions. I'd go for a one of the hydrangeas if there is enough room and light and then groundcovers, especially as you go back to the more shaded areas. Keep it simple.

Thanks so much for the quick responses! I never considered putting a bench up there but I really like that idea.

Dig Doug - Definitely love the idea of something climbing over the fence. What did you use? Do you think a climbing rose would be okay?

Nancy - Beautiful, thank you! Part of my problem is I love too many things and want to use them all. ugh. I really like the idea of the large arborvitae for a screen but I have to admit they make me a little nervous... i see too many dead ones in people's yards.

Laceyvail - I think they're hickory trees. I'm more concerned about being able to dig around their root systems to get anything in the ground around them vs. the shade.

i had no idea there was such a thing as a climbing hydrangea! i was looking at the zepherine drouhin rose, which is supposed to be shade tolerant. but thanks for the other options!

ptreckel - i know, you're right. i'm adding a couple more photos to show the small lawn in front of the wall, plus the slope/rock garden that sits at the wall's lower left with some boxwood and scrawny perennials (which I'm also going to replant). i'd love to do a ton of perennials– that was my first inclinition, but i should mention i have a crazy dog who has a tendency to trample things.

Can you provide rough dimensions? The area looks more or less triangular, so the three sides and the distance to the apex or point of the triangle.

Based on what you have already got staged or planted in that area (that we can see) the area looks far too tight to cram in all the plants showing on the mock ups - one of the reasons they are not effective for design purposes as the scale is often ignored or misinterpreted.

The other issue is that larger plants are difficult to establish in an area wth a number of large trees - the soil tends to be very rooty and hard to dig. And the trees with their dominant root systems hog all the soil moisture and nutrients.

gardengal - here's a rough plan of the area. yes, i'm concerned about the tree roots on the left. thanks!

You want to allow spacing to 5' wide for both hydrangeas. And the Pink Beauty (aka 'Preziosa') is going to be a water hungry plant until well esablished, so may need a lot of extra attention in the area you have it intended for at least the next few years.

I think it makes the most sense to scale out the area on graph paper, noting where the trees and their roots are located, and then draw in the desired plants at their full size. That will tell you how many you can fit in and how best to space them. But the presence of the trees and their heavy, aggressive root systems is always going to be a factor of what will work and what won't. I would focus on part shade plants that are drough tolerant once established. And with fairly shallow root systems that can cohabit with the trees.

gardengal - thanks. i did actually start plotting out plants on my plan, but that was when i was convinced i wanted a ton of different perennials and wasn't being realistic about my dog destroying everything. i'll definitely rethink it. yes, i know i'll have to be diligent with my hydrangea care, but i think it's worth it for the return. also think i need some boxwood somewhere in the mix for continuity with the rock garden/slope that sits to the lower left of the retaining wall and for some everygreen color. i really appreciate all of the input!