how old and large are you oaks ..

dont donfuse removing grass and weeds around a new transplant tree ... with putting stuff under a giant old established tree .. i dont know what you read .. unless you have a link.. so its hard to go beyond that ...

short of axing out major roots to plants.. or driving construction equipment under the trees ... a little digging to plant a few plants should not be a negative ...

ken

Azaleas and ornamental grasses are not going to hurt well established oak trees. The oaks in time are more likely to shade them out, particularly the grasses. In the meantime the grass will make for fine nesting material and the azalea will provide cover for nestlings that fall from the trees.

ellaboobella, Pictured below is Miscanthus sinensis, If this is the grass that you are talking about get rid of this weed. This pic was take under a power cut in a remote park in Maryland not close to a residential area. That gives you an idea how far the wind carries the seed. This thug becomes dominant and chokes everything else out. You are quoting Tallamy right? Good for you.

Any grasses you plant under an mature oak will, of course, be grasses that do well in shade--Miscanthus sp. do not. You might look at ferns, Brunnera, Pulmonaria, and Hakonechloa macra aureola is a gorgeous weeping grass. There are lots of wonderful plants for shade that will do well under a mature oak and won't harm the oak at all. Consider all the native spring ephemerals--bloodroot, trillium, Virginia bluebells, trout lilies--and others.

Thanks for all the help and advice. The oak (we have several) is mature, but I’m not sure how old, but this house was built in the 70s.

the Ornamental grasses planted very close to the trunk of the oak looks a little like the pic, but for the pink color “Poofs.” lol Sorry.. I have no idea what to call those.

Christopher, I agree about wildlife easily taking refuge under those grasses, but unfortunately theres a lady in our neighborhood who lets her cat out at night, and sometimes it stays in our small neighborhood for days on end. And I can’t even begin to tell you the horrors I’ve seen on our security cameras. Those grasses are next to our deck as well, and that’s where the cat watches for the birds.

We have many shrubs and trees etc, and a heavily wooded bluff out back, and we’re surrounded by woodland. So the areas where this particular oak is gets sun part of the morning below the tree, but that’s it.

Sorry for the cutoff on the last comment. I couldn’t delete the last paragraph or add to it.

What is more likely taking refuge in the grasses are mice and voles and that is why the cat is so interested in that spot. The one thing wildlife and native plant enthusiasts always fail to mention is the vermin attracted to lush landscapes. They talk up the birds and pollinators and neglect all the other wildlife out there.

I installed a woodland garden last year and used Carex pensylvanicum (oak sedge) under a very large Northern Pin Oak. It's too soon to tell how they'll do ( 12 nursery grown plants), but it seems like this native sedge was "designed" for such a site.