The watercolor that I’ve been using lately is the sketching set water color from Van Gogh. It’s ok, but the greens are not that great. I think I still have other water color sets from e.g. Winston & Newton somewhere in the storage/basement. But with all the remodeling in the house, I am just too lazy to look for them and use it. So my ‘temporary’ solution was to buy this Van Gogh watercolor and use it for the moment.
I had the same watercolor set from Van Gogh and I had the same problem as you with the green. I am now using another box and bought some more colours. I have now 4 different greens. The brush of the Van Gogh set is fine and perfect for drawing details.