How to grow a Rainbow Rose, Naturally
Two dutch companies, River Flowers and F.J. Zandbergen, experimented and successfully grew a rose that had its petals rainbow colored. It happened in 2004. Their idea is to split the stem into several channels and dip each one in a different colored water. This way all the colors will be drawn by the stem into petals and resultant rose will have all the colors in it. You can use the same method to colour any flowers.