The genus Iris contains 200-300 species and while there are often significant differences between the species, their stereotypical flowers are instantly recognizable to the majority of people. This vast array of species originate from areas around the northern hemisphere, in habitats ranging from desert, to swamp, to woodland. The family Iridaceae includes 80 genera, the most familiar of which are Gladiolus and Crocus which have similar foliage but different flower forms.

The typical Iris flower with its three drooping sepals, or ‘falls’, and three upright petals, or ‘standards’, is actually an intriguing co-evolutionary development between insects and the plant to ensure that no flower is self pollinated. Visiting bees, in search of nectar, brush across the stigma and deposit pollen from other Iris. They then pick up pollen from this flower as they back out over the anthers and go on their way to visit other blooms.

The name Iris refers to the Greek goddess who acted as a messenger using rainbows to travel back and forth to Earth. This is in reference to the array of color to be found in the flowers of the various species that bloom throughout the temperate growing season in sequence. While the majority are generally in the blue to violet range (especially in the wild) most of the other possible colors are represented to at least some degree.

The linear grass-like foliage is a great attribute for these plants, working as a wonderful foil for softer or more spherical plant shapes, allowing for fantastic design implications. Sword like spears usually of a medium green reach for the sky with clean lines and unerring reliability.

When thinking of Iris the first image that most likely comes to mind are the large, showy blooms of the much hybridized German or Bearded Iris (I. germanica). Grown in full sun and well drained soils these lovely garden standards have fallen somewhat out of favour due to their susceptibility to borers and rot of their rhizomes. But this is only one of the numerous species that are readily available, and it is well worth the effort to explore other possibilities, many of which are much less susceptible to these problems. Most Iris make excellent, though short lived, cut flowers.

Iris ‘Gerald Darby’

A selection from a native North American species that has its nomenclature in something of a disarray (not overly unusual these days). Commonly listed as I. versicolor ‘Gerald Darby’ and also I. robusta ‘Gerald Darby’ it is thought to be a naturally occurring hybrid between I. versicolor and I. virginiana. The most recent publication of the List of Names of Perennials indicates that the preferred name avoids the specific epithet issue completely by deleting it. Now, once you are past the confusion of what to call this plant it is well worth the effort to find a supplier and introduce this cultivar to your customers and landscapes. ‘Gerald Darby’ has the typical violet-blue flowers that personify the genus but exhibits the most amazing deep purple color in its emerging spring foliage. Unfortunately this variegation mostly fades by early summer when the blooms appear, leaving only a smattering of purple color at the base of the leaf blades. Unlike its bearded cousins, ‘Gerald Darby’ prefers a moist location for best performance even tolerating 2” to 4” (5 to 10cm) of standing water during the growing season. Full sun to partial shade is its preferred lighting level. Foliage will reach a height of 24” (60 cm) with the flowers rising a little above that. The plants will slowly spread to form a clump about 12” (30cm) across. USDA 3 to 9.

Iris ensata ‘Freckled Geisha’

Another species of Iris that prefers a moist to wet location while growing, but must be dry while dormant. From their origins in the East, I. ensata are known by the common name of Japanese Iris, or Japanese Water Iris. These plants are valued for the amazing size of their gorgeous flowers — although their often drooping standards and falls give a more flattened appearance — which often reach 12” (30cm) or more across. This particular cultivar exhibits blooms of a very impressive 9” (20cm) diameter with white petals generously freckled with violet red splashes of color that coordinate with its distinctive red violet picotee edging. A lovely contrasting bright yellow signal (small stripe at the throat of each petal) adds a splash of brightness to the flowers. I. ensata bloom in June —July, later than the German Iris. This cultivar will reach a mature height of 36” (90 cm) and a spread of about 20” (50cm). USDA 5 to 9.

Louisiana Iris

Sometimes improperly listed as Iris Louisiana, a specific epithet that does not actually exist. Louisiana Iris is instead a convenient name for any of a group of 5 closely related species and their hybrids native to the American southeast. As a group they are vigorous and extremely floriferous with colors ranging from blue and purple to yellow, pink, white and shades of brownish red. Similar in form to the flowers of Japanese Iris (wide and flattened) they are quite early to bloom usually showing in late May to early June — well before even the Japanese Iris. Large clumps can form quite quickly if the plants are happy. The foliage can reach a height of 36” (90 cm) with a similar spread. Native to swampy or bog-like conditions they are happiest in a moist to wet location in full sun to partial shade. However they can also handle regular garden soil as long as they receive plenty of moisture during the growing season. USDA 4 to 9.

Iris sibirica ‘Moon Silk’

The Siberian Iris is native to northern Asia and are one of the easiest Irises to grow in North American gardens. Foliage is much more narrow and grass-like in appearance than that of the more sword-like German Iris, and presents as a vase shaped clump in the garden for the entire season, making these great companion plants for sunny areas. These Iris are very adaptable, tolerating moist to quite dry soils and full sun to partial shade. The original species was a traditional deep violet blue, but there are now cultivars available in shades of white, yellow, pink, blue and violet. I. sibirica ‘Moon Silk’ has the most delicious shades of soft yellow and creamy white, some of the most overlooked but essential colors in garden design as they give the eye a chance to rest when viewing some of the more riotous colors that can be found in the herbaceous border. Generally reaching a height of 36” (90cm) and forming a clump two to three feet across (90cm). Flowering occurs in mid summer, after the German Iris but before the Japanese. USDA 3 to 9.