You already have a typical Brooklyn-style postage stamp yard. If you plant bushes for a perimeter, they will take up a lot of that precious piece of lawn you liberated. You already have a fine looking brick retention wall. You could consider a low-to-mid height matching brick planter-wall for your little patch of lawn. The colorful flowers within would soften the angularity of the brick wall and give a pop of color. It would also likely be lower maintenance than trimming a hedge of bushes.

It would be neither of those options for me.

I like the look of just the brick wall and grass. It shouldn’t take too long for a softwood stump to rot away - break it up a bit with an ax and keep it moist. Consider whether something behind the wall can be grown to spill some flowering stems/branches over the top of the wall to add a bit of color there.

Thanks everyone. I also have little kids. The thought of leaving it too empty makes me feel like someone would run right off it. We have a backyard but this is the front portion. It's also because the grass will be straight there's so like grass showing when u walk past hence why I thought it needed something. Is the consensus more for flowers bushes?

Also the visual with the plants on the outside portion. It's weird, in NYC we don't technically own that patch - I think it's city property. We just planted grass seed. But I'd prefer to not put plants down there yet.

It was not clear that your were talking about the upper portion. You should specify parameters, details and quirks in your initial post. I thought you were talking about the lower area. Fence it with metal picket fence as it is more transparent.

What type of flower bushes if I did those that would hang down or cascade a little?

Is your house the one on the left?

If you want something to sprawl and hang down the brick retaining wall, how about climbing roses? The kids would learn real fast to stay out of them.

A Beautybush might work well to throw some flowers over the wall. Some of the taller hydrangeas would work too. Clematis on a trellis or other support might work too - we have a ‘Huldine’ clematis that grows up a 8’ tall support and then spills down in a sheet of bloom, surfing across nearby shrubs. So there are lots of options....

Ideas:

I like the idea of a fence that is open grid so you can still see through and not block the property.

A short white picket style fence is a good alternative for your house. As you said you have kids so the fence would serve the safety purpose. It would also enhance your home’s look. These fences are durable and require minimum maintenance. A wide range of variety is available in picket fences. To learn more about picket fences visit: https://www.totalfenceinc.ca/articles/what-are-the-different-types-of-picket-fencing/