My feature plant for October is the Iris and our first Dutch Iris bloom has just opened, right on time! They are such beautiful regal flowers and definite confirmation that Spring is here to stay and the long cold Winter is over!Irises, commonly known as ‘flags’, belong to the family Iridaceae and the genus Iris, which contains 260 to 300 species, many of which are natural hybrids. The number of different types be quite confusing, but the first and major difference is whether they are rhizomatous or bulbous. Rhizomes are horizontal underground stems that strike new roots out of their nodes down into the soil, and that shoot new stems out of their nodes up to the surface. Most iris in this group are evergreen, but some go dormant, usually in late Summer/Autumn. Rhizomatous iris are either bearded or beardless. Bearded Iris have a tuft of short upright filaments down the centre of the blade, while beardless iris usually have a flash of colour, mostly yellow, at the top of the lower petals (known as falls), called a ‘signal’. Beardless iris include: Pacific Coast, Louisiana Iris, Siberian Iris and Japanese Iris. Bulbous iris have a small bulb like an onion and are dormant and lose their leaves for part of the year. They include Dutch, English and Spanish Iris, as well as Iris reticulata. The photo above is a Dutch Iris. There is an excellent diagram on the Iris Society of Australia (http://www.irises.org.au/TypesIris.htm), which clarifies the situation in a simple form. I will discuss some of the major groups in more detail later in this post. The photo below shows my Dutch Iris in the cutting garden last year.Habitat: Temperate regions of the Northern Hemisphere from Europe to Asia and across North America. They are found in a variety of habitats from dry semi-desert to colder, rocky, mountainous areas, grassy slopes and meadows and even bogs, swamps and riverbanks.History:
Iris comes from the Greek word for rainbow, referring to its wide colour range. It is also the name of the Greek goddess of the rainbow, who was the messenger of love, thus iris are symbols of communication and messages. In the language of flowers, iris generally means ‘eloquence’, after which its meaning depends on its colour : purple iris represent wisdom and compliments; blue iris symbolize faith and love; a yellow iris means passion and a white iris represents purity. The photo below is a bed of Bearded Iris of mixed colours.The iris first appeared in artwork in the frescoes at King Minos’s palace on Crete and date from 2100 BC. It became the symbol of King Clovis of France (466-511 AD) on his conversion to Christianity, the iris being known as one of the Virgin’s flower. The fleur-de-lis, a stylized representation of the iris, was the emblem of the House of Capet, which ruled the Kingdom of France from 911-1328 AD, and was also adopted as a symbol by King Louis VII in 12th century France. A red fleur-de-lis is found on the coat of arms of Florence, Italy, where it has been their symbol since 1251, as well as that of the Medici family, while yellow irises are depicted on the Quebec flag. The iris is also one of the state flowers of Tennessee. It is even found on Japanese banknotes! The back of the 5000 yen banknote depicts “Kakitsubata-zu”, the most renowned painting of irises in Japan. It was painted by Ogata Kouri, one of the most famous Japanese painters . See : http://jpninfo.com/17450. Another famous artwork ‘Irises’ was painted in 1889 by Vincent Van Gogh and was sold at auction in 1987 to Alan Bond for a record $53.9 Million. It was resold in 1990 to the Getty Museum for an undisclosed amount. Iris flowers have also been painted by Leonardo Da Vinci, Durer, Renoir, Cezanne, Gauguin and Monet, as well as my daughter Caroline, especially for this post!Garden cultivars were found in Europe by the 16th century. There was a big boom in breeding from 1830 on and by 1930, the American Iris Society listed 19 000 iris species and hybrids. There are now literally thousands of cultivars of Bearded Iris – over 30,000 Tall Bearded Iris alone! Compare the following photos to see the difference between the old (1st photo) and new (2nd photo) iris blooms.
Unfortunately, like many other plant species, hybridization to produce increasingly large, dramatic frilled blooms of a huge colour range has been at the expense of fragrance, but there are conservation groups, for example : the Historic Iris Preservation Society ( http://www.historiciris.org/ ) in America, which specializes in the preservation of heritage iris varieties, which are over 30 years old and are tougher plants with less frills, but more fragrance. New Zealand also has a Heritage Irises blog with links to Iris gardens and growers throughout the world. See : http://historiciris.blogspot.com.au/. The Presby Memorial Garden (http://presbyirisgardens.org/wordpress/) in New Jersey is a living iris museum with over 10 000 iris plants, while the largest garden in Europe is the Giardino dell’ Iris in Florence, Italy, (http://www.intoflorence.com/giardino-dell-iris/), which has 1500 varieties in its two acre garden and hosts an annual international iris festival in late May.
In Australia, irises are best seen in October/ November at specialised iris nurseries like:
Yarrabee Water Garden and Iris Nursery, One Tree Hill, South Australia : Tall Bearded Iris and Louisiana Iris : http://www.yarrabeegardenandiris.com
Sunshine Iris, Lockhart, west of Wagga Wagga, NSW in the Riverina : 300 varieties and specializes in older vintage Bearded Iris: http://www.sunshineiris.com.au/.
Riverina Iris Farm, Lake Albert, is another Iris nursery, just south of Wagga Wagga, which specializes in Tall Bearded Iris : http://www.riverinairisfarm.com/. It has open gardens on the weekends from the 8th of October 2016 to the 6th of November 2016 from 10 am to 5 pm. They are also open on Tuesday, Wednesday and Thursday and other times by appointment.
Rainbow Ridge, Burnt Yards, west of Carcoar, NSW : Tall Bearded and Median Iris, Louisiana and Californian Iris: http://www.rainbowridgenursery.com.au/
Iris Splendor, Railton, Tasmania : Tall Bearded Iris: http://iris-splendor.com
Tempo Two, Pearcedale, Victoria : Specialist Iris nursery : http://www.tempotwo.com.au
Tesselaars, Monbulk, Victoria also sells Dutch , Bearded, Siberian and Japanese Iris: https://www.tesselaar.net.au/.
Iris are handsome, herbaceous, evergreen perennial plants, which grow from creeping rhizomes (rhizomatous iris) or bulbs (bulbous iris).
They have long, erect flowering stems, which are simple or branched, solid or hollow and flattened or with a circular cross-section, depending on the species. The photo below of my gold Bearded Iris shows the basic structure of the plant.
Rhizomatous iris have 3-10 basal sword-shaped leaves, which form dense clumps, while bulbous iris have cylindrical basal leaves.Iris have 6 symmetrical lobed flowers, which grow on a pedicel or peduncle. The 3 sepals drooping downwards are called ‘falls’ and have a narrow base (haft), which widens into a blade, which may be covered in dots, lines or veins. In Bearded Iris, the centre of the blade has a tuft of short upright filaments to guide the pollinating insects down to the ovary. The blades of the iris act as a landing stage for flying pollinators. There are also 3 upright petals called ‘standards’, which stand behind the base of the falls. All petals and sepals are united at the base into a floral tube above the inferior ovary and the style divide towards the apex into petaloid branches. The Bearded Iris in the photo below is much frillier and larger than my gold Bearded Iris, shown above.
Flowering occurs from late Winter through to late Summer, depending on the species. There is a good diagram on: http://gardendesignforliving.com/a-guide-to-growing-iris-blooms-all-season/ , giving a guide to flowering times for the Northern Hemisphere. Basically, Iris reticulata starts the iris flowering season in late March to mid April, followed by Iris pumila for 2 weeks in early May; then Crested Iris for 1 week in mid to late May. Tall Bearded Iris also bloom in mid to late May for 2-3 weeks, overlapping with Siberian Iris, which are slightly later and have a shorter blooming period. Japanese Iris bloom in late June to mid July, then the iris season closes with reblooming Bearded Iris in August and September. In Australia, Dutch Iris flower in early Spring (September) and Bearded Iris bloom in October/ November.
The fruit is a capsule, which opens into 3 parts, revealing many seeds. In the desert dwelling Aril Iris, the seed bears an aril.
Iris are divided into 6 subgenera, which are then divided into a number of sections, but I will mainly focus on the more common garden iris, including the varieties I grow in our garden. All of the subgenera are from the Old World, except for Limniris, which has a holarctic distribution. The largest subgenera are marked with an asterisk *. Here are the names of the 6 subgenera:
*1. Bearded Rhizomatous Iris:
eg Table or Stool Iris: Iris aphylla
eg Bearded Iris : Iris germanica
eg Sweet Iris: Iris pallida
eg Hungarian Iris: Iris variegata
*2. Limniris: Beardless Iris:
eg Pacific Coast Iris
eg Louisiana Iris
eg Siberian Iris: Iris sibirica
eg Japanese Iris: Iris ensata
eg Large Blue Flag: Iris versicolour
eg Yellow Flag: Iris pseudacorus
eg Blue Iris: Iris spuria
eg Yellow-banded iris: Iris orientalis
eg Crested Iris: Iris cristata
3.Xiphium: Smooth Bulbed Bulbous: formerly Xiphion
eg Spanish and Dutch Iris: Iris xiphium, though Dutch iris also known as Iris x hollandica
eg English Iris: Iris latifolia
4.Nepalensis: Bulbous Iris: formerly Junopsis
5.Scorpiris: Smooth Bulbed Bulbous: formerly Juno
eg Iris persica
6.Hermodactyloides: Reticulate Bulbed Bulbous: formerly Iridodictyum:
eg Iris reticulata: white, blue and violet: see photo below from the Portland Botanic Garden.Bearded Iris
The most common iris in the garden, which is a result of a cross between an early German hybrid, Iris 5 germanica and other naturally occurring European hybrids of Iris pallida and Iris variegata, as well as wild species like Iris aphylla. There are so many hybrid cultivars, but they are divided into groups based on size:
Tall Bearded Iris Over 71cm: Largest iris and the last to bloom.
Border Bearded Iris 38-71 cm tall: Similar size flowers to Tall Bearded Iris, but shorter stems.
Miniature Tall Bearded Iris 38-71 cm tall; Smaller flowers to Border Bearded Iris; Also called Table Iris, because they are very dainty and suitable for small arrangements. Similar growing conditions to other Bearded Iris.
Intermediate Bearded Iris 38-71 cm tall. Very prolific. Cross between Dwarf and Tall Bearded Iris and require a bit more cooling and a bit more watering than the latter.
Standard Dwarf Bearded 20-38 cm tall and the shortest Bearded Iris; Suitable for borders. Dwarf Bearded Iris are easy to grow, but do require full sun and frosty Winters and loose, well-drained soil. Do not allow to dry out totally over Summer.
Miniature Dwarf Bearded Up to 20 cm. Suitable for rockeries only.
Aril Bred Iris: Arilmeds: 45-75 cm. Cross between Tall Bearded Iris and desert Aril Iris. They like very well drained soil and may die down in Summer.
A good site for more information on Bearded Iris is: https://www.claireaustin-hardyplants.co.uk/blog/types-of-bearded-irises.
For a description of the many different species, see: http://www.irises.org.au/TypesIris.htm and follow the underlined links.
Siberian Iris: Iris sibirica
Hybrids of Iris orientalis and Iris sibirica.
Native to Asia and Europe.
Beardless flowers in blue, lavender, yellow and white in late Spring/early Summer. The flowers are smaller than those of Bearded Iris and the foliage is very decorative. They do not grow in water and are not bog plants, but are very tough and can be planted in Spring and Autumn. They need a frosty Winter to flower well. Flowering time is usually November in Australia. The best situation is a damp, sunny spot and they are dormant in Autumn to early Winter.
Japanese Iris: Iris ensata
Once called Kaempferi Iris, they have been cultivated in Japan for more than 500 years and were once grown exclusively for royalty. Flowers are purple, pink and bicolours and both the sepals and petals are flat. They do not actually live in water, but like the same moist conditions as ferns. Flowering in November to December, they like damp, acid soil with cold Winters and will be dormant from Autumn to Winter.
Large Blue Flag: Iris versicolour
Grows in boggy areas and swamps in North-Eastern USA and comes in blue, violet and white.
Yellow Flag: Iris pseudocorus
Native to Europe, where it grows in swamps and boggy ground, but naturalized all over the world. Very invasive and aggressive growth, so should not be planted near waterways. Much safer contained within a walled garden like this one at Dalvui, Noorat, Victoria!
Pacific Coast Iris
From west coast of USA, they are low growing, extremely drought-hardy irises, that need a sunny spot with acid soil. They must only be moved in late Autumn to early Winter .
From the Gulf Coast and the Mississippi River area of USA. They are evergreen and one of the few irises that like tropical areas, although they will grow in most of Australia. Has flatter flowers 4 to 6 inches across and bloom in October to November in Australia. Likes similar conditions to Japanese Iris: moist rich acid soil and partial shade.
Spuria Iris :
Come from Central Europe. They usually go dormant for a while in Autumn. They grow in a wide range of soils (especially alkaline), but need a cool Winter and dislike extreme Summer humidity. Flowering in Australia is in October to November.
Dutch Iris: Iris x xiphium 70 to 90 cm tall
Beardless bulbous iris, with royal blue, white and gold flowers in Spring. A favourite with the florists. The blooms last 5 to 7 days.
Growing Conditions and Propagation:
Basically, iris like a well-drained soil, with at least 6 hours of sun a day. Full sun all day is even better, but darker-coloured varieties are probably better with protection from the hot afternoon sun. Because of the wide geographical distribution, cultivation requirements vary greatly and there is an iris for every situation.
Most Iris like to be chilled in Winter, in fact some Dwarf Bearded iris actually require frost to bloom. Bearded Iris are grown in Zones 3-9, while Dutch Iris can be grown in Zones 5-9.
Bearded Iris likes dry Summers and cool to cold Winters and a neutral to alkaline soil, which is moist during their active growth and flowering, but dry after that. Siberian Iris like damp boggy soil, shade and a frosty Winter. Pacific Coast Iris like a dry Summer, a cool damp Winter and an acidic soil, while Louisiana Iris also like a damp, wet, acidic soil. Rockery Iris like moist, perfectly-drained gritty soil. Iris reticulata likes a good porous soil in a sunny or shady spot with leaf mulch in Winter. None of them like too much nitrogen.
Plant Dutch Iris bulbs in the Autumn for Spring flowering. Last year, we ordered and planted 5 bulbs each of Discovery (Royal Blue); Hildegard (pale blue); Lilac Beauty (violet); Casablanca (white); and Golden Beauty (gold) from Tesselaars. Plant bulbs 10-15 cm deep and 10-15cm apart, pointed end up. Lift and divide every few years to avoid overcrowding. I planted them with cornflowers to hide their dying foliage after blooming.
Propagation is usually by division, more rarely seed. In the following paragraph, I will describe the cultivation of Bearded Iris:
Divide the clumps in Summer every 2to 3 years, when they become congested. Separate the rhizomes by hand or with a sharp sterile knife if necessary. Check the rhizomes for borer attack, to which they are susceptible, and discard any infested ones. A good rhizome will be the thickness of a thumb with healthy roots and 1-2 leaf blades. Plant bare-rooted in late Summer in an open sunny position. In the Northern Hemisphere, the rhizome should still be visible on the surface of the soil, where it can absorb the sun’s warmth, but in Australia, they can be covered with 1.5 cm soil to avoid scorching. My gold Bearded Iris came from our rental place and last year, we discovered some forgotten Bearded Iris clumps growing under the shade of the cumquat trees, so we divided the clumps and replanted the rhizomes singly along the edge of the Moon Bed. Already, they have multiplied profusely and I cannot wait for them to flower this Spring, so that I can discover their colours!Uses:
Highly ornamental plant, which is fragrant, low maintenance and multiplies readily. Good as a feature plant, in a border or in a rockery. Bees, butterflies and hummingbirds love them!
Floristry: Buy when the colour is visible beneath the sheath, but before the petals have started to unfurl (see photo below). They do not like preservative, as iris do not like sugar, so only use a few drops of chlorine bleach in the vase water. Do not arrange with daffodils unless the latter have been conditioned, as the daffodils’ toxic sap will affect the iris stems.
Perfume Industry and Medicine:
Grown for the production of irone, orris oil and orris root. Irone is a methylione odorant, used in perfumery, which is derived from orris oil and has a sweet floral, woody, ionone odour. Orris root is used in perfumery, potpourri and medicine and is actually the rhizome of Iris germanica and Iris pallida. The rhizomes are harvested, dried and aged for up to 5 years, during which time the fats and oils degrade and oxidize, producing fragrant violet-scented compounds, which are valuable in perfumery. Aged rhizomes are stem-distilled to produce iris butter or orris oil. This essential oil is used as a sedative in aromatherapy. The dried rhizome has also been given to teething babies to soothe their gums. Orris root and iris flowers are also used in Bombay Sapphire Gin and Magellan Gin for its flavour and colour. In the past, iris has been used to treat skin infections, syphilis, dropsy and stomach problems, as well as being used as a liver purge, however it should only be used by a qualified practitioner, as the rhizomes can be toxic. Iris contain terpenes and organic acids, including ascorbic acid, myrsistic acid, tridecylenic acid and undecylenic acid. The Large Blue Flag, Iris versicolour, and other common garden hybrids, contains elevated amounts of toxic glycoside iridin, which cause nausea, vomiting, diarrhoea and skin irritation, though it is not normally fatal.
The Yellow Flag Iris, Iris pseudocorus, used to be grown in reed bed substrates for water purification, as they consumed nutrient pollutants and agricultural runoff, but they are extremely invasive and have become a noxious weed, clogging up waterways.
Finally, a brief description of some other types of iris in the Iridaceae family:
Peacock Iris: Moraea aristata: Endemic to Cape Town, South Africa
Rare Winter-flowering bulb, with large white blooms (5 to 7cm across) with a deep, iridescent blue eye on each petal. Their undersides are also white, but covered in decorative blue freckles. They have no scent. Easy to grow, they are best left in the ground to naturalize. The foliage and flowers emerge Winter to Spring and they are dormant through Summer. The flower stems grow 20to 35cm tall and the narrow foliage grows to 40cm. Can easily be cultivated in sunny gardens with sandy or clay soils , but prefers well-drained, humus-rich soil. Grow in full sun to light afternoon shade. Water in and keep moist during active growth and keep relatively dry during dormancy. Critically endangered in the wild.
Dietes, also called Wild Iris, Butterfly Grass or African Iris: Dietes iridioides
A clump-forming, rhizomatous perennial, also from South Africa. Dietes have dark green, strappy foliage and white (marked with yellow) and mauve, iris-like flowers on tall stems in Spring. The flowers have six free tepals, that are not joined into a tube at their bases and only last one day. The flowers are followed by 3-celled capsules, containing numerous seeds, on stalks, which bend right down to the ground for easy propagation. Grow in full sun or part shade. Although tolerant of tough conditions, Dietes will perform best in well-drained soil, rich in organic material. Fertilize occasionally and water during dry spells. Do not remove flower stems, as they continue to flower for several years. Propagate by seed or by division of established clumps.
Native Iris or Silky Purple Flag: Patersonia sericea
Densely-tufted, perennial herb with short rhizomes. Endemic to the east coast of Australia and first described in 1807, Patersonia grows in dry sclerophyll forests, woodland and heath, preferring sandy, well-drained soil on the coast and ranges. Up to 60cm tall, with stiff grass-like grey-green leaves and three-petalled, blue-violet flowers in terminal clusters, enclosed in two large papery bracts, in Spring and Summer, which last less than a day. Frost-tolerant and thrives in hot, dry situations. There are 6 other species in the Patersonia genus.