Does it have small white bell shaped flowers?

ginger?

It looks like it might be either ginger or cardamom.

Yes, it is ginger. Specifically is is Myoga Ginger (Zingiber mioga). It is the flower bud of this ginger variety that is usually eaten. A pot-only plant, as it was in this garden, in my Northern locale.

FataMorgana

Here is a link that might be useful: Myoga Ginger

I was looking for a herb.

I'm not following your meaning. Ginger is an herb.

FataMorgana

Just that I always considered ginger a spice. Then again when I think of ginger I think of the root. Maybe the actual plant comes under herb.

Following on, from wiki...

Zingiberaceae, or the Ginger family, is a family of flowering plants consisting of aromatic perennial herbs.

I learn something new every day!