The bearded iris groups that are midway between the tall bearded hybrids and the dwarf bearded irises as well as the cultivars derived from the latter are known as median irises. This group of irises is not only charming, but are also extremely useful in prolonging the flowering season. Median irises bring in fresh elements to the perennial borders in your garden and, hence, they rightfully deserve to be grown in all gardens.
There are four sub-groups of median irises – standard dwarf bearded irises, miniature tall bearded irises, intermediate bearded irises and border bearded irises. Hence, when we talk of median irises, we actually mean all types of bearded irises, barring the bearded irises as well as the miniature dwarf bearded irises. However, the arils as well as the arilbred irises are an altogether different variety.
Prior to the 1950s, there were many varieties of small irises, which were mainly diploids, meaning that they all had 16 chromosomes, which is the original number of chromosomes for all plants belonging to this species. Diploids are also defined as “2n”, which means that each parent contributes half of their 16 chromosomes. Near the beginning, nearly all the small irises were developed from the Iris lutescens (earlier known as I. chamaeiris), which is indigenous to the arid regions of Spain, Italy and southern France.
In due course of time, there was a remarkable effect in the development of the intermediate bearded irises as well as the standard dwarf bearded irises, which were derived from the I. pumila’s seeds that were tetraploid (having 32 chromosomes – double the number of the original number or those having “4n” chromosomes). Subsequently, breeder collected the seeds of some other bearded iris species like the I. cengialtii, primarily tetraploids, from eastern regions of Europe and they were included in the basic stock of standard dwarf bearded, miniature tall bearded and intermediate bearded irises. Iris cultivars bred from tetraploids having double the number of original chromosomes offered various advantages, including larger size, augmented substance and vigour.
Precisely speaking, all irises that are smaller in size compared to the tall bearded irises, but taller compared to the miniature dwarf bearded irises are known as the median irises. Hence, not only the height, but even the flowering season of these irises is said to be “average” compared to other varieties.
Standard dwarf bearded irises
The height of the standard dwarf bearded irises varies from 8 inches to 15 inches (20 cm to 38 cm) and they are just a little taller compared to the miniature dwarf bearded irises. The flowers of standard dwarf bearded irises appear in a wide assortment of color combination – many of them even have attractive thumbprints and patterns on their falls. Usually, the blooms of this iris variety should appear on stalks higher than the foliage and when a plant bears multiple flowers, the blooms may even put the leaves out of sight altogether, especially when the plants are in full bloom during their flowering season. Usually, the rhizomes of standard dwarf bearded irises give rise to numerous stems, which increases the number of blooms and, at the same time, extends the flowering season, as each stem produces several buds.
At the beginning of the growing season, place these plants in containers and when they are in bloom with an array of hues, shift the containers to any important site in your garden. However, you should pull the plants out of the containers and plant them back in your garden when their flowering season is over, as it will help the plants to multiply rapidly and develop into a large clump.
These irises are very adaptable. Compared to other bearded iris varieties, the standard dwarf bearded irises possess the aptitude to endure a variety of climatic conditions. These irises can flourish in the cold northern climates and also endure more wind compared to the taller iris varieties. In addition, these irises can also thrive in more shade compared to most other bearded irises. Moreover, standard dwarf bearded irises can also endure additional foot traffic compared to the majority of other irises and, hence, are excellent for growing in garden borders.
The foliage of median irises grows nearly all through the season and develops into dense, beautiful mounds having lance-like green leaves that contribute to the texture of the garden’s borders. While these irises, in fact, are an asset for all types of gardens, they are particularly more useful as well as attractive when grown in mixed beds comprising low-growing perennial plants.
During the past one decade, hybridizers have been greatly successful in breeding standard dwarf bearded irises. This iris variety is derived by breeding Iris pumila with the tall bearded irises. As numerous standard dwarf bearded irises have been derived from I. pumila, most of them contain the genes of this species and may even come with typical spot patterns that are so akin to those of their forerunners. The spots may, however, vary greatly – ranging from small to big and some of them may have extremely contrasting hues, while it may be insignificant in others. On the other hand, some varieties may not have the spots, but come with contrasting beards. In addition, some median irises have attractive plicata patterns with the petal margins being dotted or stitched. They may come in outstanding combinations like purple on white, as in the case of the “Royal Decree”, or brown on yellow as in “Input” or burgundy on gold as in the case of “Firestorm”.
From time to time, novel colors as well as patterns appear on standard dwarf bearded irises. Some of these colors include enhanced as well as deeper oranges alongside red beards, chartreuse yellow together with red beards, pinks having blue beards and even light blue standards alongside bluish-green falls accompanied by red beards. Some flowers also have reverse amoenas, which mean that the blooms have colored standards, but the falls are white. In addition, there are flowers whose amoenas come with white standards, while the falls are colored.
In fact, the color as well as patterns of the blooms of the standard dwarf bearded irises come in such a wide assortment that there is a need for additional study of catalogs with a view to determine the precise types of these plants that can actually be grown in your garden.
Intermediate bearded irises
This variety of bearded irises has got its name from the fact that the height as well as the flowering season of the intermediate bearded irises are between that of the tall bearded iris and standard dwarf bearded iris. They are also a type of median irises that usually grow up to a height of 16 inches to 27 inches (40 cm to 68 cm) and have straight flowering stalks. The flowering stalks are branched and grow higher than the straight-growing foliage. Usually, the flowering stems of intermediate bearded irises have two branches and each stalk bears five buds.
The intermediate bearded irises produce blooms that are about 3 1/2 inches to 5 inches (10 cm to 12 cm) across. The flowers bloom at a time when the standard dwarf irises have completed flowering for the season, while the tall bearded irises are yet to bloom. Their height is more or less equal to that of the border bearded irises. However, they blooming season differs. The peak bloom of the intermediate bearded iris should be before that of the other bearded irises. The blooming season of the intermediate bearded irises varies subject to the breeding as well as the size of the blooms of this iris variety. In fact, the plants with smallest flowers bloom first.
Most of the plants belonging to the class of intermediate bearded irises comprise hybrids that have been derived by crossing the standard dwarf irises and tall bearded irises. However, few of them have also been derived by hybridizing plants of different bearded irises and other species like Iris lutescens and Iris aphylla. In fact, hybridizers have used the species I. aphylla with a view to enhance the fertility, bud count and branching of the intermediate bearded irises. While plants belonging to this iris variety have potent hybrid vitality, the fertility of this hybrid variety that has 44 chromosomes has been considerably bargained owing to their compound genetic arrangement. Consequently, the possibilities of hybridizing the intermediate bearded irises with each other to develop newer iris cultivars are very less, as many intermediate bearded irises are basically sterile.
The blooms of the intermediate bearded irises have a close resemblance to the tall bearded irises. The flowers of this iris variety are of excellent substance, besides having attractive forms. The falls of these flowers are rounded and flared, while the standards are closed and curved, often having ruffles or lace. The blooms of this iris variety appear in a wide assortment of hues and their combinations, which are also seen in the flowers of their close cousin – the tall bearded irises.
Miniature tall bearded irises
Also known as table irises, the miniature tall bearded irises have been raised for floral designers as well as small gardens. These irises grow up to a height of 16 inches to 25 inches (40 cm to 72cm). The flowering stalks of these irises measure anything between 1/8 inch and 3/16 inch across and the combined width of their blooms is not more than 6 inches. Ideally, the combined height of the stalks and the flowers of the miniature tall bearded irises should be between 21 inches and 22 inches.
The standards of the miniature tall bearded iris flowers are pleasantly aromatic and this is an added attraction of this iris variety. If the flower had a disagreeable smell, people would have discarded the seedlings of this iris, as no one would like to have the blooms of the miniature tall bearded iris for table arrangements. The blooms of this iris variety grow at a higher level than the foliage. The form of the flowers of the miniature tall bearded irises is not much ruffled and airier compared to the bigger blooms of the tall bearded irises. The typical form of miniature tall bearded irises reminds one of wildflowers.
The appearance of the miniature tall bearded irises is very akin to the contemporary delicate adaptations of the conventional tall bearded irises, which you can still see in several old gardens. Precisely speaking, the miniature tall bearded irises are, in many ways, the smaller adaptations of the tall bearded irises. They are, however, different from the border bearded irises and the intermediate bearded irises, as the size of the plants as well as the size of their flowers are somewhat smaller. In addition, miniature tall bearded iris plants are also thinner as well as more elegant compared to the other two bearded iris varieties. These plants are well-branched and have wiry stems that enhance their attractiveness.
Currently, iris breeders are engaged in enhancing the form of the miniature tall bearded irises blooms and also widening their color range by crossing the newer tetraploid cultivars and older diploid species. While majority of the present day table irises have been derived from the first-born diploid bearded irises, all the new pink hued miniature tall bearded irises have their origin in the tetraploid hybrids.
The miniature tall bearded irises bear a wide assortment of flowers and one can find amoenas having their colored falls and white standards, plicatas having dotted or stitched edges on the petals, as well as light and vivid colors. While the miniature tall bearded irises are perfect for table arrangements, they are also perfect for growing along borders and in perennial beds.
Border bearded irises
Border bearded irises usually grow up to a height of anything between 38 cm and 71 cm. The blooming season of the border bearded irises correspond with that of the tall bearded irises and they look very attractive when planted facing them, because the border bearded irises also possess the ability to endure more wind and are not buffeted about very easily. While the border bearded irises are not as popular as the other bearded iris varieties, they are available in an excellent range of forms, colors and sizes.
There are various different varieties of border bearded irises and you may love to grow some of them in your garden. Some of the favourite varieties include the “Brown Lasso” having butterscotch standards and violet-hued falls with brown edges, “Batik” having uniquely streaked white on a purple background, “Pink Bubbles” that produces flared flamingo pink and ruffled blooms, and “Ingenious” having ruby-black falls and rosy violet standards.
The flower stalks of border bearded irises grow up to a height of anything between 16 inches and 27 inches and bear flowers that measure about 4 inches to 5 inches across. The flowers appear on stiff and straight but branched stems, while the leaves are straight and also smaller compared to the flower stalks.
Earlier, there were no specific requirements for growing border bearded irises vis-à-vis the size of their blooms, slender stems as well as narrower foliage. The vigour of border bearded irises is relatively less and this has proved to be a major in growing these plants. This is mainly owing to the fact that a number of cultivars of this iris variety are just too small solely because they did not have the precise environment that would help them to attain their genetic potential. However, it was found that when the plants are grown in favourable places and provided with the right amount of moisture and nutrients some border bearded irises developed into tall bearded irises!
During the 1970s, border bearded iris breeding slowed down a little, possibly owing to the fact that this iris variety is very frustrating. In fact, a breeder may grow several dozen special hybrids of border bearded irises only to discover later that not a single one fits the size requirements of this variety of bearded irises. During the later part of the 1970s, breeders achieved some noteworthy successes in enhancing the color patterns as well as the vigour of border bearded irises. Now, breeders are optimistic that henceforth the border bearded irises will multiply consistently on their own.
The border bearded irises now contain the genes of various iris species, counting the dwarf as well as the taller adaptations of Iris aphylla, such as I. balkana and I. reichenbachii. These species have added their respective hues and patterns, in addition to wonderful proportions as well as relatively smaller flower size to the border bearded iris cultivars bred from them. However, it is important to note that dwarf iris species have not always been used to breed the border bearded irises. Consequently, the present day iris breeders can grow large border bearded iris crops and most of these young plants meet the size requirements of the border bearded irises.
Ideally, good present-day border bearded irises ought to have their stems and blooms in right proportions instead of having very small stems with blooms whose size is similar to the flowers of the tall bearded irises. On the whole, they should be compact as well as elegant, which is markedly dissimilar to the general impression one has regarding the tall bearded irises. The new border bearded irises should not require any staking, while their smaller blooms are just ideal for flower arranging. It is advisable that you use border bearded iris plants as a pleasant boundary for your sunny garden.
Aril and Arilbred Irises
Bearded Irises / Culture / Species
Evansia or Crested Irises
Louisiana or Hexagona Irises
Miniature Dwarf Bearded Irises
Novelty Bearded Irises
Pacific Coast or California Irises
Reticulata or Dwarf Bulbous Irises
Scorpio or Juno Irises