Its a well known fact vanilla ice cream are green in colour. For getting the green colour, you can use vanilla or its products which render green. There are plenty of manufacturers who sell natural green colorant.

regarding blue colour, i am not sure. I think one can try blue grapes to get blue (more of purple) colour.

Apart from this there are lots of green / blue flowers / fruits in nature. Just google it and may get some positive results for colour extraction from the selected flower / fruit. and can be extracted in backyard and can use it.

I dont think spices can render green / blue colour.

Its a well known fact vanilla ice cream are green in colour. For getting the green colour, you can use vanilla or its products which render green. There are plenty of manufacturers who sell natural green colorant.

regarding blue colour, i am not sure. I think one can try blue grapes to get blue (more of purple) colour.

Apart from this there are lots of green / blue flowers / fruits in nature. Just google it and may get some positive results for colour extraction from the selected flower / fruit. and can be extracted in backyard and can use it.

I dont think spices can render green / blue colour.