Symphonies in yellow: "Sunflowers", 1888, by Vincent van Gogh: left, at the National Gallery, and right, at the Van Gogh Museum in Amsterdam
When Vincent van Gogh died in 1890 aged 37, following a few days of lingering agony after having shot himself, the mourners at his burial placed sunflowers on his coffin. Every succeeding spring his friend and physician Dr Gachet — and later the doctor's son — would plant sunflowers on the grave. Van Gogh had first painted the blooms in 1886 when he arrived in Paris from Holland and they appear in the last picture he ever painted too. The flower stood, he said, for a sense of gratitude. But it also seems to have represented both the sunniness he yearned for, yet so rarely experienced, and the brevity of life, of which he himself became a symbol. The most celebrated of his sunflower pictures are those of the blooms in a simple half-glazed vase that he painted in the summer of 1888. He painted four versions and later three copies and the story of their creation is explored by Martin Bailey in his book The Sunflowers are Mine (Frances Lincoln, £25).
The four initial pictures were painted in a single week as Van Gogh waited for Gauguin to arrive in Arles, where the two men planned to live and work together. Gauguin grew up in Peru and sunflowers originated in South America: the pictures were Van Gogh's way of making his new studio mate feel welcome. During the week of August 20 a mistral was blowing and Van Gogh couldn't work out of doors so he painted instead what lay to hand. He planned to work on a series of 12 sunflower pictures in all to brighten Gauguin's room, a decorative scheme he likened to "a symphony in blue and yellow". In the end he settled for four, the paintings using 10 tubes of paint — each tube being the equivalent of a meal in a restaurant and all paid for by Van Gogh's faithful brother, Theo. The pictures showed compositions of three, six, 14 and 15 blooms.
After Van Gogh's death the sunflower pictures and his three copies were dispersed. One disappeared into a private collection and was last exhibited in 1948; another was destroyed in Japan by an American bomb on the same day the atom bomb was dropped on Hiroshima; one spent the war evacuated to the servants' quarters at mad Ludwig II of Bavaria's Neuschwanstein castle; while a fourth became the world's most expensive painting when it was bought by a Japanese insurance company for £25 million in 1987. The remainder found their way to museums around the world.
Two of the paintings, the National Gallery's 15 sunflowers and the Van Gogh Museum's signed copy of it from 1889, are now being reunited for the first time. The National Gallery exhibition (from January 25) will offer the opportunity to compare the paintings and will also include a technical exploration of the painter's technique. They represent, too, a perfect example of Van Gogh's fixation with his signature colour: "pale sulphur, yellow, pale lemon, gold. How beautiful yellow is!" he wrote. Yellow covers 95 per cent of the surface of the National's picture.
Van Gogh believed his sunflowers would simply "catch the eye". He was right, eventually. He sold only one painting in his lifetime and that was not of flowers but The Red Vineyard. Visitors now agree with him: the National Gallery's painting is the most visited in the collection. There is an easy way for the staff to know: the varnish on the floor before it wears through more frequently than in front of any other picture.