Commercially most perfume is coloured using colouring agents designed for cosmetics: there is a long list of them permitted by the EU.
However I prefer, wherever I can, to obtain colours by natural means and in this case that looks entirely possible: there are a great number of oils and especially absolutes that are strongly green in colour. Even a very small amount of, for example, lavender absolute or mint absolute added to your blend will make it green.
Blue isn’t quite so easy, but there are still some options. As it happens I’ve just released a mens fragrance of my own, which has a blue colour (the picture on my home page gives a true idea of the colour) that comes from a combination of Artemisia absinium
(the keynote fragrance ingredient) which has a turquoise blue colour and yarrow - Achillea millefolium
- a high azulene version from Hermitage Oils
- which has a wonderful deep blue colour even when heavily diluted. I needed so little yarrow to get the colour I wanted that it is virtually undetectable in the fragrance (and in any case fits with the herby vibe I was looking for).