Judy's idea is a simple one that would work. I don't have a green thumb so can't suggest specific plants but wouldn't a larger topiary as your middle one work? I'd do them all the same and let them grow in the space to fill it up. Paint the planters the same green and it will look "wall-ish". Btw, have you noticed your top left book shelf is sagging a bit?

Just found this vendor on etsy and a cut to fit panel can be made for you.

There are several other sellers who do the same work. You could compare prices.

https://www.etsy.com/listing/462061797/cerchi-laser-cut-screenwall-decor?ref=pla_similar_listing_top-5

Those are great ideas! Thank you!!

It didn’t even cross my mind the screen panel.
I’ll definitely look into that and see if that etsy vendor can do something I’d like.

And regarding the plants, definitely will look into a bigger topiary too, and see what I’d like best. I also thought instead of that maybe something like the picture below, but I’m afraid it will be too much.

Ps: Yep, bookshelf will actually be gone by the end of the month, exactly because of that :)

If you want to keep it somewhat open, how about a high shelf all the way across, in front of the supports. Here it is in front of a window (and lower) but the idea is there... https://www.houzz.com/photos/modern-farm-house-farmhouse-kitchen-austin-phvw-vp~6304760

Is it the only source of light for the hall?

Drywall it.

I'd think of trying a wood-type frame large enough to cover [and not show the frame on other side] -- and staple a fabric you like. 80"W x 52" ?

I like the idea of hanging plants. Greenery adds such life to a space! Try them and if it doesn't work, you can find another spot for them.

A soft glow from higher -wattage ceiling light in next room could be pretty - long track light?

And with something hung in one of the rooms, you could still place items on the bottom.

Chalkboard doors if it appeals. Not 'permanent' like drywall, but more money.

https://www.houzz.com/photos/allie-traditional-kitchen-portland-phvw-vp~9953444

Custom - sized resin, etc.... www.3form.com

https://www.houzz.com/photos/forma-design-modern-bedroom-dc-metro-phvw-vp~324370

Panel screen of whatever material - with LED in between

https://www.houzz.com/photos/high-rise-condo-modern-bedroom-san-francisco-phvw-vp~3083432

Alternatively, could you add shelves at different levels and use it as a makeshift bookcase?

I would either drywall it over, or remove the upright pieces. If you remove the uprights you may need to put a header in, if there isn't one above the space.

Decoenthusiaste made an important question. It looks like it was opened to illuminate the hallway... so you could go with cut-out panel or frosted glass in order to both close the wall and not block natural light.

Do you rent or own. If you own then just remove all the vertical sticks.