Ruth Nicol doesn't do in-between.

In life, she is a big personality. In work, she is a cracking landscape painter, with antennae ever alert to the bigger picture. And some of Nicol's pictures are big indeed. She says that four 3mx2m paintings are all she can hold in her head - and in her studio - simultaneously. But she does small very well too. Last week in the Glasgow-born artist's Edinburgh studio, I saw some totey-wee paintings which were beautifully delicate and lyrical at the same time.

One of Brownsbank Cottage, the poet Hugh MacDiarmid's final home outside Biggar in South Lanarkshire, depicts a hard-edged landscape fringed by rowan trees dripping with red berries. I keep seeing it in my mind's eye days after seeing it in the flesh. By her own admission, Nicol will "aye be whaur extremes meet". This quote from MacDiarmid's darkly epic 1926 poem, A Drunk Man Looks At The Thistle, is carved into the writer's gravestone in Langholm Cemetery, close to where he was born.

The starting point for Nicol's new work is Alexander Moffat's 1980 painting, Poet's Pub, which depicts a fictional gathering of seven of the greatest Scottish poets of the 20th century. In it, a pipe-smoking MacDiarmid is holding court in a setting which is an amalgam of the interiors of the favourite Edinburgh drinking haunts of George Mackay Brown, Robert Garioch, Norman MacCaig, Sorley MacLean, Edwin Morgan and Iain Crichton Smith.

The title, Three Rivers Meet, is a nod to MacDiarmid's assertion that he could identify any one of the three rivers - the Esk, the Wauchope, and the Ewes, which meet in his home village of Langholm - by their sound alone.

Nicol and Moffat - both Yes supporters in the Independence debate - have become friends over the course of the last year she has spent working on Three Rivers Meet. As she travelled the length and breadth of Scotland in search of the landscape which informed the work of all seven poets, subsequent discussions with Moffat helped focus her attention on the spirit of the paintings she has produced.

"I think Sandy is a pivotal conduit across art disciplines for a number of reasons," Nicol says. "He had a determination early on in his career to define Scottish painting and he still continues to do this. Through his work at Glasgow School of Art and beyond, he is also an influential teacher completely immersed in Scottish culture. Leading up to the Referendum - and after it - we have had some fantastic discussions.

"He connects decades of artists to the writers of the Scottish Renaissance of the 20th century and this has been incredibly important during the sustained period of self-reflection which has taken place over the last year. At the age of 47, I've only just realised that I'm not just an artist and a mum [she has two daughters, aged 15 and 4]. Now, thanks to making this work at such a pivotal period in Scots history, I'm a political animal."

In depicting locations as diverse as Whalsay in Shetland, where MacDiarmid lived for nine years, MacLean's Raasay, Morgan's Glasgow, Garioch's Edinburgh, MacCaig's Assynt, Crichton Smith's Lewis and Mackay Brown's Orkney, Nicol has created a remarkable portrait of Scotland. She has an innate feel for landscape, mixing up the looseness of ever-changing skies, rivers and seas with the hard edges of man's imprint on the land.

This work has been created almost as a homage to the influences which shaped her as she grew up in Glasgow during the 1970s and 1980s. Nicol's mother, actress Irene Sunters, was well known to a generation of Scots theater-goers through performances at the Citizen's Theatre, and to millions through roles in Take The High Road and Rab C Nesbitt (she played Mary Doll's mother). The artist's father, John O'Neill, was a teacher and an author, as well as an adviser in English for Strathclyde Regional Council and Principal Marker and Setter for O-Grade and Higher exams.

"They both made lasting contributions and connections to the arts community in Scotland," Nicol says, "and I have fantastic memories of growing up in Riddrie with my siblings in a household which was filled with debate."

Three Rivers Meet opens on October 13 at the Open Eye Gallery in Edinburgh and then travels to Duff House in Banff, RGI Kelly Gallery in Glasgow, The Line Gallery in Linlithgow and Park Gallery in Falkirk. Each show will be different, with art works selected specifically for each gallery . There's an added treat for visitors at Duff House, as Alexander Moffat's portraits of Morgan and Garioch will be exhibited, on loan from the National Gallery of Scotland and in partnership with Historic Scotland.