Van Gogh's characteristic impasto technique adds texture and movement within the painting, creating an energetic and expressive feeling.

His initial confinement to the hospital grounds is reflected in his imagery, from depictions of its corridors to the irises and lilacs of its walled garden, visible from the window of the spare room allocated as his studio.

Van Gogh was optimistic about the restorative effects of painting in the hospital garden, writing: "I believe that all my faculties for work will come back to me quite quickly".

[2] Van Gogh started painting Irises within a month of his one-year stay at Saint-Paul-de-Mausole, in May 1889, working from nature in the hospital garden.

[4] Irises bears a direct trace of his work there: embedded in the paint is one of the pollen cones that fall in abundance from the umbrella pines in the garden.

Bearded irises bloom for about three weeks (slightly longer if the weather is cool; more briefly if it is hot), so we can guess that these two paintings were separated by about ten days or so.

Van Gogh associated irises with Japan, where the native species were highly prized and had a prominent place in art.

Many artists found Chevreul's observations in Charles Blanc's widely distributed Grammaire des arts du dessin.

Theo wrote, "Now I still have to tell you that the exhibition of the Indépendants is open, and that your two pictures are there, the 'Irises' and 'The Starlit Night'...They have to put it on the narrow wall of the room, and it strikes the eye from afar.

“As we go down deeper into the painting, you see this wonderful violet color,” Ormond noted, explaining that it was originally created by mixing geranium lake red and blue—a combination that has since faded to reveal only the blue.

[11] Félix Fénéon, an early and avid spokesman for the Neo-Impressionists contributed his account of Irises, which appeared in the symbolist review La Vogue in September 1889.

"[9] In a video by Smarthistory, Dr. Scott Allan raises the question of how to categorise the artwork, reflecting on its intriguing viewpoint, which suggests that van Gogh may have been sitting or kneeling.