what have you been trying to grow back there?
Where in oklahoma are you? Our south area is a different zone than the north. That will affect the answer

oh and the only rosemary I know of that could overwinter here is Arp or hill hardy. But I am sure one of the smarter folks here could probably offer more varieties.

Also, what kind of soil do you have? That will influence our answers as well. If you have compacted, almost rock-hard clay soil, that's the problem. If you have loose, more-well-draining sandy loam, then it is likely your tree roots are sucking up all the water or maybe you're planting plants that need more sun than they're getting in the shade of the trees.

It also would help if you tell us some of the plants which have failed in your shady location. I can tell by the mention of Acuba that you must have really heavy shade.

I'd second the recommendation of "Arp" and "Hill Hardy" rosemary. They've been the most cold-hardy for me. There may be others that tolerate very cold temperatures, but the two that both OkiePokie and I mentioned are the ones I see in nurseries here.

Dawn

My backyard is very shady with lots of surrounding trees as well. The things I have found that best survive that environment are as follows:

Oakleaf Hydrangea (Hydrangea quercifolia)
Itea virginica 'Little Henry' aka Virginia Sweetspire
Rhus aromatica (native Sumac)
Aesculus parviflora (Bottlebrush Buckeye)
Variegated Vinca
Holly Ferns
Arum maculata
Clematis 'Nelly Moser'
Campanula 'Elisabeth'
Thalictrum flava 'Illuminator'
Adenophora - Lady Bells
Hostas - I have Sun & Substance, Blue Angel, Titanic, Night Before Xmas
Astilbes
Hellebores
Columbine
Caladiums
Jack in the Pulpit
Lobelia cardinalis - Cardinal Flower
Hellebores
Variegated Solomon's Seal
Acanthus mollis - Bear's Breeches
Elderberry
Grape Hyacinths
Hardy Begonia - B. evansiana
Epimediums - great dry shade plants, once established
Heuchera 'Raspberry Ice'

I add lots of organic matter to my soil each year such as chicken manure, and I allow the leaves to fall and decompose on the ground, which also adds organic matter and acts as a mulch.

Trees really draw away the water and nutrients, though, as mentioned, so it is difficult to maintain a garden amid trees. Their roots reach far and wide seeking out moisture.
These plants have pretty much thrived, after watering them lots when establishing them. I don't have to water them as much now.

Susan

Thanks, Susan--I've been looking for shade flowers for Oklahoma--just found you!