Garden plant seen at the botanical garden in Oct,2018.

Angelonia Species?

May be. But images are too small to see anything.

You are also not following the minimum posting size of 1000 by 800 pixels.

I will post the originals.

Adding the originals one by one since both in one mail bounced back.

Attachments (1) – 5 mb.

Second picture

Have also cropped a flower.

Attachments (2) –  4mb and 187 kb.

That looks very much like Prostanthera rotundifolia.

There are 90 species of Prostanthera and I do not know them all. Several are in cultivation and might well be found at Atlanta Botanical garden.

Seems to be Angelonia to me as well.

I have cropped the other picture.

Attachments (1)

Angelonis angustifolia ‘Archangel Raspberry’ I hope