Yes it does have a somewhat different appearance than Tsuga c. that I've seen but I really haven't seen all that many up close. And I have never seen a T. diversifolia.

I have Tsuga canadensis all over in my woods, and this looks consistent with T. canadensis. I have no experience with Tsuga diversifolia, but the photos I see on line have chubbier needles, proportionately wider to their length than the native, so I think that this is T. canadensis. Perhaps someone with experience with both will weigh in.

Sometimes T canadensis foliage can be a bit variable -- seen some that had rather Carolina hemlock-like needles (but they weren't that). Gonna be hard to differentiate between some hemlock species.

I'm leaning towards T. canadensis too. Just by all the pictures I've looked at online. There were maybe more than a hundred of them in the garden. Also the firs there looked more like Abies concolor than they did Abies firma, so maybe we can assume there were substitutions made? It wouldn't surprise me. I was wanting to speak with some certainty about this when I talk with others.

Does the particular garden have an online information about plants or even contact info you can use to ask about the particular plants you want an ID for?

Bill, was that found at the Anderson Garden? If so, it could very well be something other than T. canadensis.

Yes, Anderson Garden. I can contact them through email.

They didn't have a regular email so I could send pictures. It was just an online question service where I could only ask a question. So we'll see what they say.

Flipped over needles showing their undersides running along the centers of the shoots are visible in your foliage shots - this is a characteristic of Canadian hemlock.

But without checking on it I do wonder about the papery looking bark.

To be honest, when comparing bark via internet photos, T.canadesis appeared to have the more rugged feature to it's bark, like my picture, where T.diversifolia had a smoother texture on a mature tree.

But then, can you always trust pictures on the web. I think not.

Look at a college library for horticulturally oriented manuals like Rehder or the Bailey encyclopedias that have keys to hemlocks that are not limited to the wild species of particular geographic areas.