Patience is a gardener's virtue

"Nature for us," wrote Paul Cézanne to Émile Bernard, "is more depth than surface." His advice to the younger artist was: "Penetrate what is in front of you and persist in trying to express it as logically as possible."

Depth was what Cézanne was determined to describe in his landscapes, still lifes, and portraits. But he did not use the convention of linear, vanishing-point perspective so much as planes, or planar brushstrokes, of interrelated colors and tones. He used lines when he needed to - as "The Gardener Vallier" shows - but color, so spatially elusive, was what he used to structure his paintings.

In this way he set up a conflict, or problem, of trying to discover an underlying logic in something perceptually illogical. The more he approached its solution, the further a solution seemed to retreat from his grasp. Right to the end, however, Cézanne described himself as "constantly concerned about the goal I hope to achieve." His final painting, which this portrait of his gardener arguably is, has the bold freedoms of an old artist's work but still involves his quest to "penetrate what is in front" of him.

The portrait remains unfinished. There is, in fact, an "unfinished" character to most of Cézanne's paintings - which some of his uncomprehending contemporaries put down to clumsy incompetence. Their criticism, however, never matched Cézanne's self-criticism. To later artists, the "unfinished" nature of Cézanne's paintings was part of their vitality and honesty.

Portraits of his gardener form a significant part of Cézanne's late work. He worked on them for long periods. The gardener, like other sitters before him, must have been possessed of much patience. The artist became keen on painting people of his own generation. "I live in the city of my childhood," he said, "and it's in the look of people of my own age that I see the past again." Yet this painting, and two large watercolors very similar to it, are not at all sentimental. The gardener's stoical character, though subsidiary to the artist's interests in form, is subtly conveyed by his posture, demeanor, and stillness.

This painting is on view at Tate Liverpool, in a display called International Modern Art, through mid-2005. You can view the painting at Tate Online.