I went to a sushi restaurant where the sushi chef put some green leaves in a teapot and poured us some sweet red tea-what were the leaves?

another possibility, Hōjicha, described here as having a reddish-brown color and a caramel-like flavor: https://en.wikipedia.org/wiki/H%C5%8Djicha.

Thank you for the ideas/responses. Asking the restaurant seems an obvious choice and I have to say that I thought of that. The restaurant must have changed hands or at least chefs as no one seems to recall what I am talking about. I believe the person who suggested red shies hit the nail on the head! The teapot must have had sugar in the bottom already as the tea seemed very sweet. However...I heard recently that there is some sort of plant (camellia?) that, when mixed with some sort of substance (powder?), produce the same result. I am sorry to be so vague. The red shies will work, but in case there are any gastronomist types on this thread, I would love to know. I wish that I had paid closer attention...Thank you to all.

Why not just ask the restaurant when you were there?

Most likely shiso. Look up "shiso tea" and see if it's a match

Could be amacha tea, https://en.wikipedia.org/wiki/Amacha

Sort of speaking of which- I can recommend the tea plant (Camellia Sinensis) as a nice garden plant. It's fairly hardy and can stand some drought when established (like most Camellias) and makes numerous small, white fragrant flowers in the fall. Also very few pest problems. I'm not a tea drinker and have never tried curing the leaves but I suppose it could be done.

Tea leaves can be green. I'd call the restaurant and ask them.