Irises are members of the family Iridaceae. This plant family also includes plants like gladioli and freesias, but a casual observer will hardly find anything in common between them and the irises. On the other hand, some other plants belonging to this family are very similar in look to irises, but they are classified under different names. Some instances of such plants are Tigridia from South America, Moraea from South Africa and Dietes, which actually look identical to irises, from South Africa. However, it is worth mentioning here that the southern hemisphere is not the original home of any true iris.
Extensively distributed throughout Europe, different regions of North America and Asia, it is easy to identify irises by the disposition of their floral parts, which are always arranged in multiples of three. The flowers have six petals, arranged in two sets – which are termed the standards and the falls. The sets known as the standards are called so owing to their propensity to be vertical, while the falls have a tendency to hang down. In addition, the falls are broader compared to the standards. Nevertheless, it is interesting to note that these floral parts – the standards and the falls, are just ornamental and do not have any role in the plant’s reproductive process.
The standards as well as the falls of irises have three style arms each that are clearly visible when one carefully observes the flowers. These style arms having distinctive colors spread out from the bloom’s center, lying over the falls and also contributing to the attractiveness of the flower. Nevertheless, these style arms of irises also have a particular purpose – in fact, they are distensions of the ovaries, which enclose the egg cells of the plant. The ovary becomes enlarged after pollination and develops into the seed pod. The ovaries, styles, stigmas as well as the anthers together comprise the sexual part (seed forming part) of irises.
The irises have an extremely alluring appearance and their bizarre color combinations, which are attributed to the different flowering parts, are not just meant for humans to wonder at the amazing sight. However, these are largely responsible for making us become enamoured with this plant. The irises actually show off their beauty to draw pollinating insects. A particular attribute of the falls, which also serve as a landing strip for the insects, actually enhances the beauty of the flowers. This, in turn, allures these insects to go closer to the bloom.
This special feature may be a dynamic dazzling signal, or just a band of contrasting colours or a frilled crown in bearded iris varieties. If you spend a few minutes close to a flower on a sunny and warm day, you will notice the bumblebees fly directly to the slender slot produced by the style arms extending over this portion over the falls. You will suddenly find the bee disappearing, as though there is a hidden trapdoor, hungry for the nectar located at the bottom of the flower. As the bee comes out it carries the anthers, thereby helping to fertilize the irises.
The genus comprises over 200 iris species. Several of these species have hybridized naturally growing in the wild, thanks to cross-pollination by various insects. As a result of this, occasionally botanists find it difficult to differentiate between true species and those that have been hybridized naturally, especially when they discover any “new” species. When we talk about a true species, we actually denote a plant whose characteristics are entirely different from those of the other plants belonging to the same genus. Even as new genetic information is revealed, botanists continue classifying the species and there may be some name changes now and then.
While hybridizers continue to develop new cross-breeds or cultivars, we notice magic transformations. While flowers of specific series gain an assortment of colors, there are changes in the shapes of blooms of other species. In several cases, the falls become wider and may be even more horizontal, especially in the instance of Japanese irises. On the other hand, in several instances, the standards become less erect.
The floral parts of a plant are denoted using the term “substance”. It has been found that petals which are more substantial actually have a propensity to last for a longer period, both on the plant itself and also in the form of cut flower. Moreover, petals that are more substantial are also more resistant to wind, heat and rain. On the other hand, a flower’s charm depends on its fragility and when the substance of the petals is increased through hybridizing it cannot be regarded as an improvement of the species. When we use the term “texture” we actually refer to the surface of a plant’s floral parts. The texture may be smooth or paper-like silken or velvety or even glossy or matted.
In fact, hybridizers started developing larger flowers that were more ruffled, richer in hues and further flaring in form ever since chemical breeding of tetraploids (plants having cells containing four chromosome sets rather than the normal two sets of chromosomes) and cross breeding of natural tetraploids (especially in the instance of bearded irises) started. Apart from the flowering parts the hybridizers also concentrated on improving the different other characteristics of the plant. Very often they created plants with thicker and greener leaves and stalks, while exaggerating the substantial of the petals as well as their velvety texture. In fact, connoisseurs of iris may certainly be obsessive towards their beloved flower.
At the same time, hybridizers try to enhance the overall performance of irises in gardens by developing plants that are further floriferous and healthier and will bear more branches that will bloom more than once every season (remontancy). They also look to create plants that are able to endure greatly varied climatic conditions. They keep trying to create an iris that is truly red. In fact, a number of Louisiana irises developed by hybridizers come very close to being truly red.
Nearly all gardeners opt for irises because of their striking hues or for their characteristic form. However, as members of the Iridaceae plant family, the foliage as well as performance of the plants all through the season is also vital design factors. In spite of everything, the foliage, irrespective of whether it is pleasing or irritating, will always be there – even long after the flowers have withered away. Precisely speaking, foliage of all irises defines the form of a particular species.
However, the foliage of some irises turns out to be less appealing after their flowers have withered away. The Reticulatas, a variety of iris that produces tiny blooms during spring, is an excellent example of this. Nevertheless, the plants still require their leaves to provide them with nourishments with a view to survive for the ensuing season. Therefore, it is best to plant the irises that bloom early in the season in a place where their foliage would remain concealed by fresh growth of the plants that develop later in the spring.
Although another variety, called the Dwarf Bearded irises, also bloom quite early in spring, their foliage remains attractive till the middle of summer. Unlike the Reticulatas, foliage of these irises continues to provide fans with erect pale green leaves. These plants look attractive and enhance the beauty of the garden when grown facing borders and among perennials that are low growing and sprawling.
Conversely, Siberian irises form high elegant fountains comprising excellent foliage akin to fine grass. The foliage of this iris variety forms a wonderful feature of your garden till they wither away in the fall. Hence, once you have been enticed by the flower of a particular iris species, you should also carefully consider where these plants will look best in your garden.
Before concluding, it is important to talk a little about the soils in your garden, whose composition may vary significantly. Sometimes the soil is too alkaline or extremely acidic and their comparative measure is described as their pH level – for instance, if the pH level of a soil is 7, it is considered to be neutral. On the other hand, any soil having a pH level of 6.5 or even below suggests that its composition is acidic and the intensity of the soil’s acidity goes up, as the figure decreases. Similarly, if the pH level of a soil is over 7 or even higher, its composition is considered to be alkaline. The alkalinity of the soil increases with the increase in the number.
A number of irises have a preference for alkaline soil, while there are others that grow well in an acidic soil. Therefore, it is extremely vital to provide the right type of soil for the right iris species. Similarly, different types of irises require soils containing different levels of moisture. Hence, providing the right amount of moisture is also important. Before growing any iris species consider its natural habitat and then try to provide the plant with the required conditions as far as possible.
It is apparent that if your garden is at sea level, you can do little or nothing to elevate its altitude. However, you can certainly provide the other conditions required by your favourite plants. For instance, depending on the requirement of your favourite iris, you can make sure whether they have a soggy ground or keep it well drained or have something in between. Similarly, you may also include the required nutrients to the soil with a view to modify the chemical composition of the soil. You can maintain or increase the acidic composition of a soil by adding decomposed animal manure, agricultural sulfur, leaf mold and pine needles. On the other hand adding dolomite to the soil or treating the soil with lime will help to enhance its alkaline composition.
Irises in the garden
The anatomy of irises
Landscaping with irises
Pests of irises
Diseases of irises
Vegetative propagation of irises
- Aril and arilbred irises
- Bearded irises / culture / species
- Bulbous irises
- Evansia or crested irises
- Japanese irises
- Louisiana or hexagona irises
- Median irises
- Miniature dwarf bearded irises
- Novelty bearded irises
- Pacific coast or California irises
- Reticulata or dwarf bulbous irises
- Scorpio or juno irises
- Siberian irises
- Spuria irises
- Tripetala irises