The Iris Flower
The iconic shape and multitude or color variations of iris flowers have charmed gardeners for centuries.
The iris has a long history of cultivation and hybridization, resulting in a genus with over 260 species. Novice iris enthusiasts should not to be daunted by such a wide selection, not when growing irises and iris gardens is so rewarding.
The genus Iris has numerous species, many of them natural hybrids.
The genus has been subdivided into six subgenera:
- Iris, bearded rhizomatous irises, including Oncocyclus, Hexapogon, Psammiris, Pseudoregelia, and Regalia
- Limniris, beardless rhizomatous irises, including Limniris and Lophiris
- Xiphium, smooth-bulbed irises
- Nepalensis, bulbous irises
- Scorpiris, smooth-bulbed irises known as “Junos”
- Hermodactyloides, reticulate-bulbed irises.
Iris is the Greek word for “rainbow,” referring to the wide variety of colors found among the many species of iris plants. In Greek mythology, Iris is the personification of the rainbow.
Most bearded iris originated in central and southern Europe. The Oncocyclus and Regelia bearded irises are native to the Near East. Most beardless irises originated in Asia. Iris Versicolor, also known as the Blue iris or Blue Flag iris is native to the United States.
Description and Characteristics
Iris plants have long stems, with basal, sword-shaped leaves, making the flowers good candidates for cut flower arrangements. The most popular irises are bearded irises, which contain one or more symmetrical six-lobed flowers.
Three sepals droop downwards and are called “falls.” A tuft of short, hair-like extensions upon these falls are referred to as the “beard.”
The Oncocyclus and Regelia irises, collectively referred to as “arils,” are especially valued for their wide range of colors.
While difficult to grow in cooler climates, the arils have been crossbred with other irises, making them easy to grow in almost any climate.
The greatest significance of the iris is its connection to the decorative or symbolic fleur-de-lis. While the French “fleur de lis” literally translates as “lily flower,” it is generally accepted that the symbol is a stylized version of Iris Pseudacorus.
The 18th century French naturalist, Pierre-Augustin Boissier de Sauvages, helped to legitimize this claim, pointing out that the “lis” in the phrase may have referred to Luts, a river in the Netherlands bordered by irises, where many French lived around the time the phrase was coined.
He further states:
“This flower, or iris, looks like our fleur-de-lis not just because of its yellow color but also because of its shape: of the six petals, or leaves, that it has, three of them are alternatively straight and meet at their tops.
The other three on the opposite, bend down so that the middle one seems to make one with the stalk and only the two ones facing out from left and right can clearly be seen, which is again similar with our fleurs-de-lis, that is to say exclusively the one from the river Luts whose white petals bend down too when the flower blooms.”
The fleur-de-lis symbol has long been associated with Christianity, with the three upward petals of the iris representing the holy trinity, and may be the reason so many monarchies used fleur-de-lis in their heraldry. Fleur-de-lis remain popular today in symbolism and architecture.
A yellow iris is the symbol of Brussels, chosen because Saint Gaugericus Island was carpeted with the wild iris. The iris is the birth flower for those born in February, as well as the state flower of Tennessee.
Cultivation and Care
How to plant iris flowers depends upon available soil, light, and moisture. Iris should be planted 10 inches deep in prepared, fertilized soil.
The taller varieties bloom a bit later than the shorter varieties, which begin flowering in April. Iris bulbs are best planted in autumn for spring bloom.
Other types of iris worthy of note:
- Siberian Iris tolerates very dry soil.
- Iris Reticulata, or Dwarf Iris, is a spring bulb that can tolerate heavy clay soil.
- Dutch Iris, also known as Purple Iris, is a bulbous iris popular with florists, which can be force bloomed year round.
- Iris Pseudacorus grows well in moist soil or even shallow water, but can be invasive.
- Iris Laevigata is a popular choice for shallow water or edging ponds.
- Iris Ruthenica grows as well and as easily as bearded irises, without the beard.
- Dietes Vegeta, known as African Iris, isn’t an iris at all, although the 3 top sepals resemble those of the iris.
- Remontant or Reblooming Irises are not a variety of iris, but rather techniques used to promote more than one flowering in a single season.
Both rhizomatous iris and bulbous iris needed to be divided every 2 to 3 years. Dividing keeps irises blooming and makes the plants less susceptible to pests and disease. Divide irises after they finish blooming by digging around the plant, lifting it out, then separating the rhizomes or bulbs.
Diseases and Pests
Diseases that effect irises can be prevented by applying fungicide in fall and early spring (to prevent fungal leaf spot) and by keeping plants free from debris (to prevent bacterial leaf blight and fungal crown rot).
Treat rhizomes infected with bacterial soft rot with a chlorine based cleanser. Garden sanitation is the best defense against the iris borer caterpillar.
Orris root, derived from the rhizomes of Iris Germanica, or German Iris, is used in perfume and medicine. Orris root is also used to flavor and color gin.
The rhizomes are dried and aged up to 5 years, which degrades and oxidizes the oils of the roots. The aged rhizomes are distilled to produce an oily compound, known to perfumers at “iris butter.”
Although the true red iris flower remains elusive, few flowers hold such a wide range of colors as does the iris. It is this extraordinary palette, as well as the striking shape of the iris, both in the garden and as a cut flower, that make it so easy to become captivated with this perennial flower.
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