The portrait will be created using 4,000 metres of jute which is being shaped over Ban an Loin by artist Martin McGuinness in tribute to both the poet and the fabric that was central the development of Blairgowrie, where the Henderson was born on November 11, 1919.
The installation, which will form over a hectare of hillside, will help launch the new Cateran Ecomuseum, a new "museum without walls" which will tell the story of eastern Perthshire and the Angus Glens.
Its aim is to connect people and place to the history of an area that spans back at least 6,000 years.
Artist Martin McGuinness said he had to learn "a lot of new disciplines" to make the ambitious design fit comfortably in the challenging mountainous landscape.
Strong winds and frost have also added to the challenges, the artist said.
Mr McGuinness added: "The portrait is facing Ben Gulabin where Hamish’s ashes are scattered. I hope he would approve – he has certainly been an inspiration for me and I am proud to be able to make my contribution to the 100th anniversary celebrations of such a legend of Scottish culture."
The portrait will form one of the launch pieces for the Cateran Ecomuseum, which has around 80 points of interest on its itinerary with more due to be added next year.
Clare Cooper, co-founder, was inspired to set up the outdoor museum after being inspired by examples across Europe. Another similar project can be found on the Isle of Skye.
She said: "The ecomuseum is really of our time. The big museum are struggling, completely understandably, and have massive buildings to manage as well as huge tranches of staff.
"We want to be very light touch as well as warm and welcoming.
"Our aim is to really engage people in the heritage on their doorstep. We have an abundance of the most amazing heritage right here, from 6,000-year-old stone circles to the Iron Age and the Picts to various myths and legends. The idea is to connect people to these stories in the landscape that helped create them."
Schofield’s Dyers & Finishers in Galashiels have sponsored the dying of the Jute for the Henderson portrait with Invercauld Estate and farmer Stephen George allowing access to the land.
The Henderson installation has been inspired by portraits of the poet by Scottish Realist painter Sandy Moffat.
Henderson, who died in 2002, spent the first five years at the Spittal of Glenshee before being schooled in England at Dulwich College in London and then at Downing College, Cambridge.
He is considered a key figure in Scotland's 20th Century folk revival and made more than 9,000 recordings of working and travelling people from all over Scotland.
He put down the stories and songs of people such as the Stewarts of Blair, Jeannie Robertson, Flora MacNeil and Calum Johnston and preserved an oral tradition dating back hundreds of years.
Henderson served as an intelligence officer in Europe and North Africa and was a communist whose political activities aligned him with the the peace movement, the Anti Apartheid campaign and the campaign for Scottish Home Rule.
A lecturer and research fellow at the University of Edinburgh's School of Scottish Studies, he wrote songs in addition to poetry, one of his most famous being ‘The Freedom Come-All-Ye.
Angus McNicol, Estate Manager for Invercauld Estate, said “The cultural heritage is of huge importance to us at Invercauld so we are delighted for this project to be taking place on part of the estate. It will undoubtedly help bring greater focus on Hamish and his connection with Glenshee and do so in in a truly innovative and inspiring way.”
Pete Crane, Head of Visitor Services, Cairngorms National Park Authority said, “The Cairngorms National Park Authority is very pleased to be working closely with the Cateran Ecomuseum as it launches its first phase. The Cairngorms is an inspiration to many and the cultural heritage of Glenshee is something we are keen to help promote and we are delighted to have been able to support this celebration of one of Scotland's great cultural figures and his connections to the Glen."