HOW TO GROW IRIS BULBS
The iris bulb comes in many different sizes, colours and shapes. It has foliage that is sword like which is very attractive when the plant is not in full bloom. The special feature of the iris flower is it has three petals called the ‘standards’ and three outer petal-like sepals that are called the ‘falls’.
Irises are basically divided into two large groups called the rhizome irises and the bulbous irises. Within these two groups you can find many cultivars and hybrids. The bulbous iris generally grows from bulbs that need a dormant period after blooming. These bulbs are generally smaller than the rhizome irises and produce blossoms smaller in size than the blossoms of rhizome irises.
The iris bulbs with thick stems are called rhizome irises. These rhizome Iris grow horizontally and are found either underground or partially underground. These bulbs produce leaves that are sword like that overlap each other. The most popular species of rhizome irises are the Bearded, Beardless and the Crested irises.
The bearded iris has two additional parts to the standards and falls; they are the stigma flaps and beard. The beardless variety has stigma flaps, standards and falls but no beard. Instead, they usually have crests. Crested irises or the Evansia iris has standards, falls and stigma flaps.
There is also a ridge found on the fall of the blossom that is like a crest. This is why these irises are considered similar to the beardless iris. They spread freely through underground stems while producing flat flowers in shades of violet, blue and white. These flowers and leaves are usually found on stems like bamboo shoots and vary in height from 50mm to 2000mm (2 to 80 inches).
Examples of bearded irises are Dwarf Bearded Iris, Intermediate Bearded Iris, Miniature Tall Bearded Iris, Border Bearded Iris, Tall Bearded Iris and Miniature Dwarf Bearded Iris.
Examples of beardless irises are Siberian Iris, Dutch Iris, Blue Flag Iris, Yellow Flag Iris, Japanese Iris and Louisiana Iris.
Iris bulbs are not only cultivated for their colourful beauty, but also for medicinal and cosmetic purposes. When bruised with wine, the juice that is found in fresh Iris roots is said to be “a great purge for dropsy”. The fresh roots of the iris germanica are, supposedly, able to cure complaints of the lungs like coughs and hoarseness of the voice. The juice of iris bulbs has been used as a cosmetic to help remove freckles from the skin. The Iris also has a pleasant perfume that is widely used in the perfume industry.
GROWING IRIS PLANTS
If you plan to grow iris bulbs some care should be taken to improve soil conditions. It is best to use a slow release fertilizer to improve the nutrient value of the soil. Use compost, well rotted manure to improve the organic state of the soil. Make sure that the fertilizer and organic matter is worked into the upper 100mm to 150mm (four to six inches) of soil. Crested irises grow best in wooded areas that have good drainage and partial shade.
Rhizome irises grow through root separation so, when taking cuttings of these irises, it is important to have some root and a leaf or two in the section that is to be planted. When planting the rhizome, make sure that the rhizome is near the surface and the roots are under the soil. Leave a space of 200mm to 300mm (eight to twelve inches) between the single rhizome irises you plant.
The hole that is dug for planting rhizome Iris has to be about 100mm (four inches) deep. Add a tablespoonful of fertilizer to the bottom of the hole. Heavy soil needs some gypsum worked into it. You can plant the rhizome at an angle [45deg], they will right themselves - thats how I do it!.
CARING FOR IRIS BULBS
It is beneficial to spread a thin layer of compost at the base of the plants every spring. Make it a habit to cut the flower stalks to the base of the plant once the flowers fade. You can encourage second blooms on the reblooming types of irises with the prompt removal of faded flowers and consistent watering.
Trimming the dead foliage and pruning back healthy leaves to a height of four to five inches in autumn is good practice and spread a layer of mulch on frozen soil.
Mulch will prevent the roots from heaving out of the soil during alternate freeze and thaw cycles. If you do find some heaving has occurred in the iris bulbs don’t try to force the plants back into the soil. Instead, cover the rhizomes, and the exposed roots with more soil.
Make it a point to divide bearded iris rhizomes every four to five years during late summer. Each division should have one or two leaf fans. But not important, I've had bare rhizomes strike, but don't plant them deep
