You are so very welcome!*
I know what you mean about the heat.* It's supposed to get to 100*F here today and the humidity will make it even worse!* :(
Keep in mind that most of a tree's roots are in the upper 12" to 18" of soil.* Planting intensely in the root zone can make the tree compete with plants for nutrients and the plants compete with the tree for moisture.* Of course using natives will help as they are adapted to such a situation.* You'll just have to be careful not to add more then 1" to 2" of soil and/or compost mixed with soil to the planting area and not to damage the tree roots when you dig.* You'll also need to be sure you don't pile mulch or soil against the trunk of the tree and bury the rootflare.* You probably already know all this though.
I'll ask the landscaping company what their thoughts are on planting around trees however, I like to do my own research because unfortunately, you can't even trust the pros. Sometimes, they don't know what they are doing.
Unfortunately many employees don't know that much about native plants.* Sometimes they don't know much about plants at all!* :?* Did you use the Garden Watchdog site I gave you to look for native nurseries in your area?* You may have to mail order what you want if you can't find it locally.
The other day I went to a nursery (shrubs and trees) with my long list of native plants. Most of the plants I wanted they didn't have. That guy said: "You have quite unusual requests...". UNUSUAL?? These are native plants for crying out loud!
By ornamental I'm thinking you mean sterile with no berries.* Inkberry aka Ilex glabra has male and female plants, so they could be thought of as 'ornamental' in the sense that they don't produce berries.* Generally the word ornamental is just a term to describe it's use in the landscape or one that flowers and doesn't produce any fruits, therefore sterile.
I asked him about inkberry and he didn't even know they carry berries. He said he has never seen and berries so his shrubs might be ornamental ones (??). He probably has never seen them because they are so tiny. Is there such a thing as ornamental inkberry?
I think that all depends on which extension service and who answers the phone.* I've found the info I have gotten to be variable.* Sometimes the person at the other end of the phone simply reads from a book and I've also heard recommendations of toxic chemicals.* Since you know as much as you do, you should be able to sift out the info you don't want, or possibly educate them.
I heard that the extensions (Master Gardeners) are also good places to ask for advice.
I've learned that just because a plant offers berries for the birds, it doesn't mean it's good for the area in which you live.* Japanese honeysuckle is a great example of that.* It produces berries for the birds, but the birds droppings contain the seeds which sprout in the wild and choke out the diversity of a native habitat.
Oh, one more question: In one area (sunny) I would like to either plant creeping firethorn or cotoneaster. They have tons of berries that birds like. Should I take one over the other? Any of them invasive (I haven't read anything about that). I think they are both not native but I am thinking of planting one of them since it seems to be great food for the birdies.
I have read that firethorn aka Pyracantha has become invasive in some areas.* I wanted to plant some with yellow berries but found it's potentially invasive in Maryland.* It's listed as a low value food for birds here.
You can search for invasives here by state or plant name.* These are considered noxious weeds so those that are cause for concern won't be listed.
You might find this site helpful for searching for info on invasives.
You can do a google with terms such as:
firethorn + invasive + North Carolina
Pyracantha + invasive + North Carolina
Hope that helps,
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.