Well, don't go giving your builder the stinkeye about the trees. Around here all the subdivision folks get all gooshy over the little stands of trees the builder leaves in the yard. Thanks to compaction, direct damage, and removal of the other trees that were helping to buffer the wind, the trees are down in 5 years anyhow.

If it's going to be a rental and you're expecting the renters to maintain the beds, keep the perennials to an absolute minimum.

How are the deer? (don't say "tasty")

A renter may be more easy to maintain some evergreen shrub,such as barberry,loropetalum,boxwood...
{{gwi:21421}}

Not a landscaping reply but rather a concern...
Why are the house and driveway below street level? Have you had a heavy rain yet? Was there any water in the garage?

The driveway angles down then back up (hard to see) so there will be a line of drainage along the middle but no flooded driveway thank goodness. We back up to wetlands which is great for no neighbors along the back but I had not thought about the deer yet! My only previous serious attempt at gardening was ended abruptly all in one night by deer...

I like the loropetelum idea. I also think two evergreens anchoring the house on each side would help, its such a tall home. Maybe a large arborvitae "the dark green would go with the blue". I think evergreen dwarf hollies would go well along the bed, maybe some forsythia "yellow would look good with the blue in spring". Just some ideas.

I'd also suggest it might be more pragmatic to use evergreen or deciduous flowering shrubs for the color rather than perennials if you have rental/maintenance concerns down the road. Most of the more common perennials will need regular dividing and replanting at least every 2 to 3 years, although some such as Daylilies are less demanding. If you have deer, definitely stick with stuff they leave alone. Beyond flowering shrubs, you might also consider shrubs with different foliage tones to give year round interest without all the work. I'd suggest giving all shrubs enough space at initial planting to avoid the need for pruning to control size; again it will make it easier for renters to maintain. You might also consider using bulbs which naturalize in your area and come back each year, planted within low growing ground covers to give seasonal color. I'd expect things like Muscari species, Daffodils, Crinums, Lycoris, Ipheion and Hymenocallis would all do well in your area. Some interesting evergreen foliage shrubs if hardy in your area might include Camellia sasanqua, Daphne odora marginata, Osmanthus heterophyllus 'Goshiki', dwarf Ilex cultivars, etc.

Thank you for your help and suggestions!