[4]: 9  Her health and eyesight deteriorated notably in 1953, and by 1958 she felt too unwell to run her home in Peaslake, and joined fellow illustrator Molly Brett in Cornwall in 1958.

[1]: 135 Tarrant began her career by designing Christmas Cards, but it was her book illustration that brought her success and fame.

[7] Among the publishers she produced cards for were the Medici Society,[note 1] Hale, Cushman and Flint of Boston, Massachusetts, C. W. Faulkner, and Humphrey Milford.

After moving to Peaslake in Surrey she took a course at the Guildford School of Art, where she met and befriended the illustrator Molly Brett.

[5] She enjoyed a long and fruitful association with The Medici Society, who published her postcards, calendars, prints and other works.

[7] Horne notes that "Her delicately coloured and rather sentimental watercolours and pen and ink drawings have remained extremely popular to this day.