Unusual Tea

I was in my company's lunchroom, and was intrigued by the tea that one Chinese co-worker was preparing to make. It looked like a little bag of broccoli florets. I asked her about it, and she offered me some to try. She explained that it tastes kind of sweet, and that she got it from a Chinese friend of hers, that this herb comes from her hometown, that likely it is the only place that one can get it. Always one to try new things, especially unusual teas, I said that I would like to try it. Having steeped it for 10 minutes or so, I took my first sip. It did indeed taste kind of sweet, also a little bitter underlying, and I swear that I have tasted it before, somewhere, but I can't quite place the memory. But it tastes quite good, this co-worker of mine said to her friend that she liked it, and was gifted with a bag of it. I took the remains of the herb home to show my brother-in-law and my sister, they had never seen it before either. Even afterwards, it smells slightly bitter. If anyone can provide a clue as to what it might be, that would be great.