What to put in these planter boxes?

[GreggleC]

Hi guys
I have these nifty cedar planter boxes which I want to fill with tallish plants to add some color in front of the grey fence behind the boxes.
I was hoping to do some tall grasses maybe with some smaller plants spilling over the front but I was also told grasses need strong sunlight all day. I’m looking for any and all ideas to get me started.
The boxes are about 13” tall (not counting the legs), by 13” deep and 48” wide, with slatted bottoms for drainage.
I live in Philadelphia and the boxes get pretty steady sun from about 8:30 am-on this time of year.
Willing to entertain ideas for any types of plants/ flowers/ grasses and so forth that will maybe grow to 12 inches or more in height.
Perennials are preferred but treat my situation like part of your garden and suggest away!
Again, than you. Thanks in advance for any and all of your tips!
Greg

 

[Meadowlark]

How about going for pollinator attracting plants? Butterflys, Bees love 'em.

I grow black eyed Susans, coneflowers, garden phlox, milkweed, dahlia, etc. in my pollinator attractor garden...and each is perennial here in my zone.