Siberian irises are known for their beauty and elegance. Growing them in your garden or along the border adds a special element to them. When the plants are in flower, the delicate blooms seem to drift as butterflies over the narrow, lance-like leaves. When the blooming season of Siberian irises is over, their attractive foliage contributes to an attractive and unswerving value to the garden’s texture.
Siberian irises are among all most popular as well as most familiar beardless irises. In fact, Siberian irises have narrow leaves, which is itself a great design advantage. The beauty of these irises is enhanced manifold when the branched flowering stalks – each of which bears about nine or even more blooms, top the foliage. In fact, the effect is really amazing.
According to botanists, Iris sanguinea and Iris sibirica are two main beardless Siberian iris species, which have been cultivated for more than two centuries. A plant of the damp meadows having its origin in northern Italy all through the western region of the Lake Baikal in Russia and central Europe, Iris sibirica is an attractive iris species that has been grown in many gardens since long. The blooms of this iris have a violet-blue hue and they generally have darker veining. The color of the flowers of different cultivars bred from Iris sanguinea varies from chattiest white to dark violet blue.
On the other hand, Linnaeus was the first to record as well as name Iris sibirica in 1754. Currently, the Sibiricae series includes a number of iris species. The Sibiricae belongs to the section Limniris, which is again a member of the sub-genus Limniris, which is a beardless iris variety. Originally, I. sanguinea was called I. orientalis and Thunberg was the first to discover as well as describe this iris series in 1794. Iris sibirica has its origin in the region on the eastern side of Lake Baikal through Japan. Nearly all the cultivars of Siberian iris have been obtained from I. sanguinea and I. sibirica.
Apart from the two Siberian iris species discussed above, botanists have identified eight other iris species in the Sibiricae series and all these species have their origin in eastern and central Asia. These species were discovered and named during the period between 1875 and 1933. All plants belonging to the Sibiricae series are rather tall and all these species flourish in wet soil in un-crowded woodlands and mountainous pastures.
The color as well as the form of the Siberian irises vary greatly. While their color may vary from verdant green to glaucous blue green leaves, which are slender and straight. The foliage of these plants grows from slender rhizomes. The plants develop into tall clumps that make particular statements in the landscape of your garden, thereby offering a focal point that augments the beauty of the plant bed or border. Usually the blooms and the flowering spikes are proportionate in size and height with each other; Siberian irises have tall flowering spikes that may sometimes bear small flowers, stylishly swaying over their foliage.
The flowering stalks of Siberian irises are well-branched and this can really be advantageous provided the flowers as well as the stalks have enough space between them and do not come in each other’s way. Characteristically, the flowering stalks of the plants have two main branches, as a result of which, the flowers appear on three separate levels. Ideally, the bracts of these beardless irises should be proportionate to the flowering stalks – not too long or wide. In addition, the bracts should also retain their color as well as remain healthy even after the flowering season is over. In fact, iris breeders as well as growers highly value the fact that the buds of these irises bloom in a long succession. In effect, this attribute can help to prolong the flowering season significantly.
The elegant blooms of these beardless irises should also be proportionate to the plant itself. Compared to the normal, but tailored blooms, those that are ruffled are usually more delightful. To a great extent, the beauty of the Siberian iris flowers are influenced by their falls – which may range from slender to round and even from horizontal to vertical. Usually, the narrow, strap-like falls are not very attractive and, hence, are unwanted. On the other hand, rounded falls or those having oval forms arching downwards are more sought-after. So are the falls that are more flaring in nature.
The standards of Siberian iris flowers also differ greatly in their shape, size and position. While some standards are quite unremarkable, there are others that are somewhat large, domed or even arched. In the end, it is the general effect as well as the elegance of the blooms that is important. The flowers of Siberian irises may also come in atypical textures – for instance, glossy, silky, velvety, metallic or rough. In fact, when we talk about texture we most refer to the falls’ surface quality that has an affect on the color of the flower, as they either absorb or reflect light. Ideally, the flowers of Siberian irises should stay fresh for a number of days together.
The colors of Siberian irises also vary from almost black to purples to wine reds, to pinks, lavenders and blues, whites and even yellows. The hue of the blooms should be clear and clean and they should not change considerably until the flowers become mature.
According to majority of growers, Siberian irises are not only dependable, but can be grown without much difficulty. Generally speaking, these beardless irises need more water and a soil that has an acid pH. This is contrary to the requirements of the bearded irises, which can flourish even with less water, but need a somewhat neutral soil. The beardless irises can be grown almost in any place, but they will produce fewer flowers, even if they do, when they are grown in shaded locations.
Soon after the flowering season of the Siberian irises is over, the plants start growing new roots and this appears to be best time to divide Siberian irises. Hence, you can divide and plant the Siberian irises successfully in July or August when their flowering season is over. Dividing and planting these irises at this time of the year provides them with sufficient time to develop new roots and re-establish themselves in the ground well before the arrival of the cold season.
On the other hand, several gardeners have claimed that they have successfully planted the Siberian irises in the beginning of fall. Early spring is another good time to divide and transplant these irises. During this time of the year the plants are less than 3 inches or 4 inches tall. Irrespective of which of these times you decide to divide and plant the Siberian irises, ensure that you give the rhizomes enough time to start growing fresh roots prior to the harsh winter or hot summer sets in. Ensure that you place the rhizomes in a horizontal manner with their foliage side facing upwards to the soil surface so that the apex of the rhizome is about 2 inches to 3 inches under the surface of the soil.
When the plants have established themselves in the soil, they will be adapting readily with the landscape, bearing flowers every season like the dependable naturalized daffodils. However, even after being established, majority of the Siberian irises garden cultivars require sufficient moisture and an acid soil. These plants possess the aptitude to endure droughts quite well. While the plants require ample moisture, they also prefer a well-drained soil. When you are growing Siberian irises, you should add sufficient humus, compost, sphagnum peat moss, properly decomposed manure and other organic substances to the soil on a regular basis. Several iris growers suggest that the pH level of the soil should preferably be around 5.8, while there are others who claim that the soil pH is not of much importance when growing Siberian irises. Nevertheless, there is enough evidence suggesting that when these plants are grown in a soil containing lots of organic materials, they are able to endure an assortment of environmental factors, counting the soil pH, compared to plants grown in soils containing more minerals.
Although the fact remains that it is essential for growers to provide sufficient organic materials and a steady level of moisture to Siberian irises, you may also find some exceptions wherein plants of this iris call will flourish even in alkaline (basic) and heavy soils. Even if they don’t do very well in such soil types, the plants will at least endure the alkalinity or the heavy soil.
If you want to divide Siberian iris clumps with a view to distribute them around in your garden or when the clumps spread beyond the area allocated for them, it is advisable that you work on them on a cool and refreshing day. When you decide to divide and replant the Siberian irises, you should ensure that all the divisions contain no less than six or, preferably more, foliage fans. At the same time, you need to be careful to protect the roots from becoming dry when you are engaged in replanting the divided rhizomes. Dig sufficiently large planting holes so that the roots can be spread out properly. Having planted the rhizomes, press the soil lightly into the planting hole and, subsequently, water the recently planted irises properly.
- I. sibirica
- This Siberian iris species is found growing in the wild in a large stretch in Europe extending from the western regions of France and Switzerland, across Russia, the erstwhile Yugoslavia, Bulgaria, northern parts of Turkey up to the Caucasus. I. sibirica plants lie dormant during the winter and their grass-like, elegant foliage reappear in spring. The blooms of this iris species come in a violet-blue hue and are beautifully highlighted at their falls’ haft (base) with white stains, which appear as veins in the primary color. Compared to the height of the leaves, the flowering stalks are taller and they usually grow to a height of over 32 inches (80cm). As a result of this, the flowers are visible even from a distance. I sibirica is a typical “butterfly” Siberian iris species. The blooms of this iris plants have a subtle, slender contour. The falls of this iris species are drooping, while the standards are stiff and erect.
- I. sanguinea
- This Siberian iris species has its origin in Siberia, China, Japan and Korea and in several ways resembles I. sibirica. However, the flowering stalk of this iris is relatively short and it is branchless. On the other hand, the blooms of I. sanguinea are bigger compared to those of I. sibirica and they usually never rise higher than the foliage. The blooms have a comparatively darker hue – more profound red-purple with more intense veining on the haft (base) of the falls.
- I. chrysographes
- Native to China, Tibet and Burma, this Siberian iris species is just spectacular – the plants are slender, sophisticated as well as inconspicuous. Ernest Wilson collected this species in Sichuan way back in 1908. The flowers of I. chrysographes have a rich purple hue with delicate golden markings that resemble an antique script, from which it derives its name. The blooms are pleasantly aromatic and emerge either in the latter part of spring or in the beginning of summer. One variety of I. chrysographes called var. rubella produces reddish wine hued flowers, while another bears black flowers.
- I. clarkei
- This iris species also has its origin in the “roof of the world” – Tibet, Nepal, Burma and India. Charles Baron Clarke collected this species near Darjeeling in India in 1875 and introduced the plant to the West. This iris plant has unusual solid stems. The flowers of I. clarkei have nearly horizontal standards and pendent falls. The color of the blooms of this iris varies from violet to shades of blue and they appear during the beginning of summer. The flowering spikes of I. clarkei are branched – each having as many as three branches. The foliage of the plant is glossy and broad.
It is said that the plants grow so profusely in the wild in some places in the eastern Himalayan range that they are cut, dried and used to feed yaks and horses.
- I. delavayi
- In 1884, a French missionary named L’Abbe de la Vaye discovered this Siberian iris species growing in the swamps of China’s Sichuan province. He was the first to introduce this iris, which is native to China, to the West in 1890s. I. delavayi is among the tallest Siberian species and often grows up to a height of 5 feet (150 cm). Even the foliage of this plant is the widest among its group. The flowering stalk of I. delavayi is properly branched; with each branch bearing about six to seven blooms having a dark violet blooms and having a signal patch along with white veins. The falls of these flowers are pendent or drooping, while the standards are nearly horizontal.
Found growing in the swamps in the place of its origin, I. delavayi is an excellent bog garden plant. This iris species blooms between the beginning of summer and mid-summer. Growing these plants from their seeds is relatively easy, but it is necessary to hand-pollinate the flowers, since they are promiscuous by nature.
- I. wilsonii
- Plants of this iris species grow up to a height of roughly 30 inches (75 cm) and produces grey-green leaves. The flowers of this iris are somewhat large and have a light yellow hue, whose beauty is further enhanced by violet veins on their falls. Compared to the I. forrestii, this is a more vigorously growing iris species and blooms during the end of summer. The flowering stems as well as the leaves of the plant are equally tall.
- I. forrestii
- This iris species is relatively shorter compared to others and grows up to a height of anything between 14 inches and 16 inches (35 cm and 40 cm). One side of the leaves of I. forrestii is glossy, while the other side is dull. Moreover, the leaves are also very shorter compared to the flowering spikes.
The color of the blooms of I. forrestii is clearer compared to that of the flowers of I. wilsonii. The flowers of this iris have more slender falls that have slightly veined. In their initial stage of growth, the standards are erect, but they soon become curly outwards. Compared to the Sino-Siberian irises, the plants of I. forrestii are less robust. They need to be watered properly during the end of the summer with a view to prevent the plants from desiccating.
- I. bulleyana
- This Siberian iris species also has its origin in China. Earlier, growers doubted the heritage of I. bulleyana, as many believed it to be a cross developed from I. forrestii and I. chrysographes. Nevertheless, as more and more plant seekers began exploring China, it was found that I. bulleyana is a species itself, but it comes in various different forms.
This iris plant grows densely and grows up to a height of approximately 16 inches (40 cm. The standards as well as the falls of the flowers of the most familiar forms of I. bulleyana species are somewhat rounded. The flowers of this iris species have a deep indigo hue with white splash in the center and deep bluish spots and veins.
- I. dykesii
- This is a hybrid iris that has its origin in the Siberian irises. It bears resemblance to the vigorous I. chrysographes form, producing bright and dark violet flowers having yellow and white markings on their falls. This iris variety is not found growing in the wild. Similarly, it is also rarely cultivated.
- I. typhifolia
- This iris is said to be a cousin of I. chrysographes. It was not cultivated earlier, but has been made available for cultivation recently. This is a lean, but graceful plant that produces very tall, curly, slender foliage. The flowers of I. typhifolia are deep blue having pendent (drooping) falls. The beauty of the falls enthuse growers to preserve this iris despite the fact that it is disinclined to bloom each season.
- I. phragmitetorum
- There was a time when people collected this Siberian iris species in China’s Yunnan province. There is no information regarding this iris being cultivated.
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