Elizabeth Rosemary Ziar [nee Rowe] was born in the Sheaf of Wheat public house, and throughout her long working life she remained faithful to the spirit of West Cornwall. She was known as 'Ro' to early friends, and Rosemary thereafter. Her mother, Grace Rowe [nee Trembath] had artistic ability and Rosemary excelled from a young age, winning national prizes for her illustrations and design whilst still at school.

In 1937 she enrolled at the Penzance School of Art under the inspirational principal James Lias who guided and nurtured her talent. WW II interrupted her studies and she joined the Land Army; later she fondly recalled picking bunches of violets while working in the fields of Penwith. After the war she returned to painting and exhibited with the NSA. She returned to art studies at Leonard FULLER's School of Painting at the Porthmeor Studios, St Ives.

Her work became increasingly experimental and her more traditional water colours began to give way to much bolder styles and more vibrant use of colour. In 1972 her paintings were first accepted at the Paris Salon, and thereafter her work was shown internationally in Italy and France. She won the Diplome d'Honneur at the Biarritz International Salon and the Coupe d'Antibes at the international exposition of paintings and sculpture in Juan-les-Pins. From that time her work was purchased by collectors from North America to New Zealand.

In 1991 Rosemary published Good Morrow Brother, a series of illustrated local stories centred on the land lying between St Ives and St Just, based on the recollections of her aunt, Mabel Trembath. Mabel's colourful memories also included recall of D H Lawrence's regular visits to the pub when heading to St Ives with his wife, Frieda. Rosemary's maternal grandfather was Madron Trembath who had been the mine captain at Geevor Mine. After his death, his wife Grace remarried Thomas Job, who subsequently became licensee of the Sheaf of Wheat Public House, which is where Rosemary's mother, also Grace, gave birth to her. Rosemary was able in her book to record and illustrate with line drawings - capturing the spirt of West Penwith at the beginning of the 20th century in both image and text.

She married the Penzance dentist, Ian Ziar, and the couple had one son.