TP Flanagan, who has died aged 81, was one of Ireland’s most accomplished landscape artists. A prolific painter, and equally at home working in oils and watercolours, he had many one-man shows, in Northern Ireland and the Republic. In 1971, his work was included in the international exhibition, Rosc: The Irish Imagination in Dublin.

Rosemary Kelly, chairwoman of the Arts Council of Northern Ireland, this week said: “Throughout his long and very distinguished career, TP Flanagan established himself as one of the most illustrious and inimitable Irish painters of his generation. In a long and rich tradition of landscape painting in Ireland, he ranks among the best. His place in Irish art history is assured.”

This newspaper’s art critic Aidan Dunne wrote: “He was without question the pre-eminent Irish watercolourist of the latter half of the 20th century. His command of the medium was exceptional by any standard and his signature style, with compositions of great elegance and poise built from flurries of fast, calligraphic brushstrokes was exceptional.”

Born in 1929, he was brought up by two aunts in Enniskillen, Co Fermanagh. He was educated by the Presentation Brothers at St Michael’s grammar school and at Enniskillen technical college.

As a child he spent time in Sligo where one of his aunts ran a school of needlework. She encouraged him to paint, and he began studying art in Enniskillen under local teacher Kathleen Bridle.

In 1948, he enrolled at the Belfast College of Art, where fellow students included Basil Blackshaw and Kenneth Jamison.

After completing the four-year course, in 1954 he began teaching at St Mary’s College of Education, Belfast. He remained there for 28 years, eventually becoming head of the art department.

He began exhibiting his paintings in 1958, and held his first solo exhibition in 1961. He exhibited on a regular basis during the 1970s and 1980s at the Hendriks Gallery, Dublin, and Caldwell Gallery, Belfast. In recent years he was represented in Dublin by the Taylor Galleries, where some of his work was shown this month.

The distinctive landscapes of Fermanagh, Sligo and Donegal became the core of his subject matter as a painter. He developed a technique and manner that were particularly fitted to capturing the soft, atmospheric light of Ireland’s western seaboard.

As a younger painter he concerned himself with the physical structure of the landscape, often examining small areas of the terrain. Later, in composite, non-representational pictures, he explored perceptions of the landscape and ideas of how “place” becomes important to people.

Later still, however, the mood and atmosphere of the scene, rendered in representational terms, came to hold his attention.

He was uncomfortable with his work being termed “abstract” or “representational”.

“I never consciously say ‘I’m going to paint an abstract picture’. You spend a certain period arranging the motifs and managing shapes. If you take a sense of narrative and content out, you get abstractions. But there’s no such thing as a totally abstract or totally narrative painting.”

Donegal was important to him since the 1960s when he and his wife Sheelagh went on holiday with Seamus and Máire Heaney to Gortahork.

Heaney dedicated his 1969 poem Bogland  to Flanagan after being inspired the artist’s painting Boglands  for Heaney.

Along with his wife Flanagan was an important presence in the cultural life of Northern Ireland. Their home was a meeting place for poets and actors, and their circle of friends included John Hewitt, Mary O’Malley and Colin Middleton.

Last year at the Ormeau Baths Gallery he exhibited works related to the Troubles. One painting, Victim, was a response to the murder by the IRA of his friend Judge McBurney. Another painting was titled A Frozen Lake . “I felt we were frozen into attitudes.”

A major retrospective of his work from 1945 to 1995 was held at the Ulster Museum in 1995, and also travelled to Dublin, and Gothenburg, Sweden. That year also his work was included in the exhibition, A Century of Irish Painting, which toured Japan.

His work is represented in the collections of the Ulster Museum, arts councils of Ireland and Northern Ireland, Dublin City Gallery, The Hugh Lane, Irish Museum of Modern Art and the National Self-Portrait Collection, Limerick.

A former president of the Royal Ulster Academy, he also was a member of the Royal Hibernian Academy. He was awarded an honorary doctorate by the University of Ulster.

Speaking last year at a ceremony in Belfast to mark Flanagan’s contribution to the arts, Seamus Heaney said: “He has been faithful to the ancient artistic impulse which is to bear witness to the wonder of the world and give glory to it, to make it firm by giving it form. His vision of the landscapes of Fermanagh and Sligo is as unmistakably his own as Paul Henry’s vision of Connemara, and his paintings of west Donegal have a stark lyric power and deep personal significance for me.”

He is survived by his wife, Sheelagh, daughter Catherine and sons Philip and Anthony.