What kind of large tree is in the photo? Because if it has an aggressive root system, the new plants you put in may not thrive. They may look good now, but won’t grow well with root competition,

I had trouble growing hydrangea under big trees. Hostas too. They shrink from year to year.

Hellebore does well. My laceleaf weeping Japanese maple has done surprisingly well. Lonicera nitida (boxleaf honeysuckle) does well and is evergreen. Most of your heucheras can be pulled forward 6-12".

hi! @chloe00s! Its a sweetbay magnolia tree. The roots are not invasive. The hostas have thrived since last year in that area

I’m in the Northeast, so not familiar with sweet bay magnolias. I guess I’ve never seen magnolias with big trunks like that - not like the smaller magnolia varieties we have here.

You will get more impact by clustering the same variety of hosta together. I usually cluster mine in like groups of three. Not lined up, but curved or in a triangle shape with space between them for future growth. Same with Huchera by color. For impact. I place them in pots on the ground and then stand back to see how they look. Remember, these perennials will grow over time and can be split and used. You might also consider Astilbe, which come in a variety of colors. And, when clumped together, look great. Then, if you like, plant annuals once all of these plants’ blooms are gone. You could also try clumps of cinnamon ferns (which grow really tall and spread) or Japanese painted ferns. My zone is 6a and I have deep shade in parts of my yard. Century old pin oaks. These are the plants that do quite well. Along with annuals in pots where I can catch sunlight!

Dry shade and wet shade take different shade plants. My suggestions above are for dry shade. Epimedium and pulmonaria also do well in dry shade.

Astilbe needs to be kept consistently moist. Golden hakone grass does well in shade and morning sun but it doesn't like to get too dry. Heuchera actually prefers morning sun--otherwise they won't bloom well.

Yes, hosta will thrive at first. I have two shaded areas under trees. One is under a 60' tree, and I have divided my hostas and tried them there. They do much better under my 12' Japanese maple.

IMO do not plant any more stuff and let what you have grow to maturity . Gardening is not an instant reward it takes tome for plants to settle in and begin to grow. I love hostas but some get huge and need space so study about the needs for the plants not the looks of them IMO a happy plant always looks great where as plants planted for where you want them are often not happy. BTW I love hellebores maybe try them but they do like moisture and I found out this year they like all their leaves removed in the early spring to get the flowers to grwo tall and showing. They spread and are honestly no work other than removing the leaves .