The way I see it, the blank wall has one possibility and that is as a backdrop for a proportionately sized planting arrangement. The most likely possibility of plants that fit would be an arrangement of 3 small, multi-trunk trees (12' height ... made of what would otherwise be known as large shrubs) where two are at the back row (a few feet from the wall) and the third is centered between and in front of them, as a 'front row.' They would be limbed up to half their total height and sitting in a bed of groundcover that is substantial in size. In fact, the bed would also encompass the existing tree. If you'd imagine a 12' circular bed with the existing tree centered in it, that would be a major part of the bed. Then, in line with that same tree, extend the front edge of the bed straight over to the drive and parallel to the house front wall, fine tuning the details as to what makes sense. (Thus, the front-to-back depth of the bed would be roughly equal to the same distance that the tree is in front of the house, where that measurement is made 90* from the house facade.) The multi-trunk trees would be spaced such that the the width of their finished form fits comfortably within the confines of the brick wall width, excluding the entrance area. It seems that an effort is being made to obscure the entrance door. I think this is opposite of what the goal should be. I'd remove whatever screen is in front of it and widen the drive with an abutting walk that goes directly to the entrance area. There ought to be 25 square feet of seasonal color planted left of the entrance door.

My sister had a very generic back yard/patio. A few years after moving in they decided to re-do the entire back area. She had 3 landscape firms draw up plans, explaining that she wanted each to provide their best ideas and bid on the project. She picked the one that best fit her needs, but did end up incorporating some ideas from all 3.

I assume by modern you mean more up to date. Not necessarily modern style like sharp corners, colder tones.... I love what you did and I think adding black trim would be amazing. Remove the landscape. You don’t need much by the porch. You need some by the right side of the house and for that I’d do something neat and simple. Two rows of boxwoods? I would for sure update the walkway. Maybe the same whitewash brick in a herringbone pattern. And can’t wait to see the new shutters. This is such an awesome home!! Love it. Love what you did. Looks amazing and will look even better!!

Yours is one of the better looking and nicely designed exteriors that I've seen on Houzz. I like the composition, scale and proportion. If you want to keep shutters on your home I would suggest replacing what you have with appropriately sized operable shutters. It's a bit hard to see in the photo but if your door and sidelights have 80's decorative glass I might consider replacing to update the look. You might even consider replacing the door and sidelights with double entry doors. I would suggest looking at your landscaping - especially thinning out some of the shrubs in front of the porch. Just to say again - you have a lovely home!