The pop art of Andy Warhol typically comes in simple lines and strong colours. This series is a bit different. The sketchy lines are the same but the colour variations are unusual and sublime. The Flowers (Hand-Coloured) portfolio from 1974 is a coloured version of the silk screen printed Flowers (Black and White) from the same year. Every print has a unique watercolour hand-colouring that was made by a studio assistant. The edition was 250 and there are 10 motives so I guess Warhol needed the assistance. Warhol very rarely used this technique - the only other time was in the 1950s. I've put together three of the same print to get a feeling of the variation in colour.
Bruce Museum in Greenwich, Connecticut, exhibited their Flowers prints earlier this year. According to this exhibition Warhol's inspiration for the Flowers came from wallpaper samples and from the book Interpretive Floral Designs by Mrs. Raymond Russ Stoltz (South Brunswick: A.S. Barnes, 1972) which he interpreted using an opaque projector.
The book Interpretive Floral Designs also featured Japanese flower arrangements, and in my opinion Warhol's fascination with ikebana is the obvious driving force behind the Flowers 1974 series. The same year as the Flowers were printed Warhol met Sofu Teshigahara, headmaster of the Sogetsu school of ikebana, in Tokyo to take Polaroid pictures for a portrait that he wanted to make. I have not read Raymond Russ Stoltz's book, but to me several of the prints in the Flowers series seams to be freestyle Sogetsu school ikebana arrangements. It would be great if someone who has the book could check this up and let me know.