Van Gogh: the Spiritual Struggle of Irises

Irises, by Vincent van Gogh, painted 1889, a year before his death.

Vincent van Gogh is one of the most famous artists who has ever lived and this painting Irises is widely reproduced.  It's very easy to see the lone white iris as the "one who stands out from the crowd," and this is perhaps autobiographical for van Gogh, that he felt himself standing out from others, but, van Gogh specifically called this Irises, not wildflowers or garden with purple and white, or some other title.   Therefore, thereby and therewith, "irises" must be a clue.
Some notes about the character of irises...

The "harsh" conditions under which iris flowers
thrive reminds us of the Way of the Cross,
and how the difficulties, pain and suffering
of the Cross brings out the flowers
of virtue and the fruits of the Holy Spirit.

The rougher the conditions are, the better irises grow; it's best to leave their roots exposed, don't give them much water or attention.  It's rather common that if planting all blue irises, a white one, or two, will also come up.  And last but not least:  irises are practically impossible to kill.
With this in mind, let us imagine a soul that God is looking upon and shaping, as the potter with his clay.
Blue is the color of wisdom and green the color of hope, white is the color of faith and purity, brown is the color of humility.

An iris known as "the blood iris."  As the iris opens up its petals,
it symbolizes Christ stretching out His arms upon the Cross
and how we are to open our hearts to Him.

Throughout the Bible, there is a plethora of images of the soul has a garden, and God as the gardener (think of the very first garden, Eden).  Van Gogh had spent the first part of his life as a preacher, so he was very familiar with the Bible and with those important images that are used by the faithful even today for spiritual development.  For van Gogh, the Irises are a painting of his soul.
Wisdom (the blue irises) grows upon the stems of hope (the stalks of the irises) and when there is great wisdom, there is also faith (the white iris that has sprung up).  But it is all planted within the ground of humility, and it is because the soul must suffer the Way of the Cross (as irises grow better when they suffer), so, too does the soul God longs to perfect.

Notice how the irises seem to be "blown over" on the left side of the canvas:
it symbolizes the Holy Spirit "breathing" upon us and how it seems that, when
we are bowed down by the weight of our crosses, we are also feeling the Presence
of the Holy Spirit.  The irises on the right side of the canvas are nearly
"writhing," showing that they are growing.

There is a final note to be added:  the background.  The orange and yellow flowers are usually cropped out of the popular reproductions of this painting, but their vibrant color and the great number of them suggests that there is the crowd that van Gogh is standing out from, but not necessarily wanting to.  The yellow and orange signifies life, and vibrancy, all the things that van Gogh's life wasn't.  It seems like he's divided the garden into two:  his soul, and the souls of the "worldly."  He longs, at times at least, to have that "easy" kind of life, but he has painted his Irises to remind himself--so close to his death--that in following God, he has chosen "the better part."