Siriol studied Textile Design, specialising in printed furnishing designs before establishing her name as a botanical artist in the 1980s. She exhibited widely including a solo exhibition of nearly 100 paintings at Kew Gardens Gallery in 1992. She is renowned for the fluidity of her watercolours, going straight in with a brush and no pencil. Recently, Community Arts projects have taken much of her time and she has moved into oils alongside watercolour. She takes inspiration from the beauty of the earth, its nature, colours and textures. She taught in a large number of classes for Dr Sherwood.