(Species: Iris - Family: Iridaceae)


Iris and its origins

A native of northern hemisphere temperate climates, the iris is a very ancient species, however cultivation and its use in the gardens of Europe, only began in the 1800s. It can grow in a variety of habitats ranging from swamplands to mountains and even in desert conditions.     


There are over 200 species of Iris which have various classifications but the simplest horticultural classification divides them in to rhizomatous and bulbous groups, relating to how the plant grows, whether it is from a creeping rhizome or a bulb. 


Rhizomatous Irises:  Have thick stems that grow horizontally underground, or partially underground.    They feature long, spiked, sword-like leaves that appear in dense clumps.


Bulbous Irises In drier climates, irises tend to grow from bulbs.  The bulbs require a period of dormancy once they have bloomed in order to recharge the bulb.  Bulb grown irises tend to be smaller than a rhizomatous iris.     


A symbol of majestic beauty, the plant produces distinctive and showy flowers that are often fragrant.  Irises name derives from the Greek word for “rainbow” relating to the extensive range of colours that the flower is available in.


Seasonality: the Iris in flower

Irises can bloom all year, depending on the variety but most are in flower in spring or summer months.  The flowers produced have a characteristic shape combining drooping, wing-like and upright petals.    Most species are fragrant.


Irises are available in a wide spectrum of colours and fantastic tones; they can be blue, yellow, pink, red, purple, white, orange and even black.  


Each species differs in height, ranging from 15cm to just over 1m and one of the most common varieties, German Iris (Iris Germanica) can grow to 80cm or even 1m.


How to Plant: Iris

For best results, an iris should be cultivated in an area of your garden that gets full or partial sunlight. 

Both rhizomatous and bulbous species thrive in a fertile, humus-rich soil that it slightly acidic and features a loamy, sand texture for excellent drainage.  Prepare the soil by adding nutrients in advance to guarantee a good bloom.  Compost, peat moss or well-rotted manure should be worked into the topsoil thoroughly. 


Rhizome planting should take place in early autumn to give them a chance to bed-in before the winter frost arrives.  Bulbs can be planted later in the season. 

Rhizomes should be planted with 12cm spacing; they will only need to be half covered and planted just under the surface to allow them to photosynthesize.  Bulbs should be placed 10cm into the ground.  


Propagation of the Iris

The type of iris dictates the propagation technique.  Rhizomes are easy to propagate. When the blooming period is over, simply remove the rhizome from the ground and divide it evenly to produce a number of new and viable plants.


For bulbous irises, propagation is also by division; offsets are cut from the bulb during its dormant period and replanted immediately to produce a section of new plants ready to bloom in the following season.