Jill Barklem, who has died of pneumonia aged 66, was the creator of the Brambly Hedge children’s titles, a richly imagined and beautifully illustrated series of stories that are a fine example of the pastoral tradition in children’s books. Inspired by her observations of the countryside around Epping in Essex, where she grew up, Jill created the series on the underground as she commuted to her degree course at St Martin’s School of Art in central London. Hating the overcrowded trains, she transported herself to a place of her own imagining that offered peace, space and friendliness, populating it with a community of mice.

The first four Brambly Hedge books – each set in a different season – were published simultaneously in 1980, thus creating from the outset a year-round introduction to Jill’s wonderfully imagined, small-scale world. Together, and mostly in the illustrations rather than the words, the four books, Spring Story, Summer Story, Autumn Story and Winter Story, introduced and defined the busy and charming lives of Jill’s anthropomorphic, fully dressed mice, primarily Mr and Mrs Toadflax and their children, but also their friends and family, who live in the roots and trunks of trees and hedgerows.

The first Brambly Hedge titles were quick to find success, and were followed by seven more, including The Secret Staircase (1983), Sea Story (1990) and, finally, A Year in Brambly Hedge (2010). All the titles were adapted for television; Winter Story was first broadcast in the UK on Christmas Day in 1996 and in the US in 1997. Merchandising included Royal Doulton china, collectibles from Border Fine Arts, and chocolates.

Visually in the tradition of Beatrix Potter and Alison Uttley’s Little Grey Rabbit stories, and originally created primarily as picture books with an audience of young children in mind, they soon became almost as popular with adults, who loved both the beautiful artwork and the complete world that Jill had created. Translated into 13 languages as foreign publishers fell for their English charm, they have now sold more than 7m copies.

Jill was born in Epping, the daughter of John and Ivy Gaze, who ran Pynes Stores, a family-owned department store in the town. At Loughton high school she suffered a detached retina that allowed her to skip all sports and concentrate on art and botany. After St Martin’s, she wrote a handful of picture books for Lion publishing and later contributed illustrations to some of their religious books. In neither was she able to include her visions of the English countryside, and always felt these books were less than her best.

In 1977 she married David Barklem, an antiques dealer. She had spent five years creating and researching the Brambly Hedge world, but when she took her work to publishers it was the lack of a storyline and the absence of any humans in the books that proved a stumbling block. Her unsolicited submission to William Collins, later part of HarperCollins, was languishing unnoticed until a phone call from Jill prompted Jane Fior, then commissioning editor of children’s books, to invite her to bring in her portfolio.

“Jill had a portfolio of lots and lots of pictures of mice and the structure of a mouse world,” said Fior. “Her craftsmanship was extraordinary. You only had to open the portfolio to know she was something special. But there wasn’t a story. Instead there was the idea of the community of mice.” Fior was immediately taken by the potential of Jill’s idea and the quality of her work, and sent her home with a four-book contract. “The intensity of Jill’s vision was clear from the beginning,” she said. “She wanted the world to be a wonderful place and she wanted to create a community where that would happen – even if it was only a fictional one.”

As Fior noted, the books came out in the 1980s, a time of political unrest and widespread unemployment. Subliminally, some of the reason for their success may have been that people were looking for something that Jill was offering – a safe place where people were nice to each other. “Although Brambly Hedge is a hierarchical society complete with a squire and his wife and imbued with a great sense of noblesse oblige, it is a place where the young and the elderly are looked after by everyone, and there is something very reassuring about that,” said Fior.

Jill’s love of the English countryside and her exceptionally observant eye for nature meant that her closely focused illustrations of trees, hedgerows, piles of leaves and luscious seasonal berries were as botanically correct as they were painterly. Her mice, too, were properly mouse-like, even while the stories about them, many of which are about sustainability, self-sufficiency and survival, are very human.

Using each of the seasons as a background to a simple story – a birthday picnic in the spring, a summer wedding, an autumn harvest and a winter festival celebration – the stories celebrated the natural world and encouraged young readers to take notice of it. Jill used the colour that suffuses her illustrations skilfully to reflect new moods as the seasons change; weather and light are vividly reflected as are the evocative colours of the seasons – rich and warm autumnal colours and lighter and cooler tones for spring.

Jill immersed herself in the world she created. She was absorbed in the smallest details of everything from the blossom on a tree to the cogs of a machine. Her study and kitchen were both piled high with dried flowers, shells, nuts, feathers – anything and everything she could collect and use to inspire the Brambly Hedge world. A good cook, she made sure that every recipe for the wonderful food enjoyed by the mice at picnics and feasts could actually be made from foraged ingredients. She adopted the same approach to the mechanical implements she created within Brambly Hedge; all the machinery in the mouse mill and dairy had been trialled by Jill in miniature working models.

In 1994, however, she had an operation to remove a brain tumour, and although the procedure was successful, she subsequently had a number of health issues, including declining eyesight that effectively brought her charming world to a premature end.

She is survived by David, their children, Lizzie and Peter, and two grandchildren, Timmy and Emily.

• Jill Barklem, children’s writer and illustrator, born 23 May 1951; died 15 November 2017