IRIS or FLAG (Iridaceae)
, the lovely “Messenger of the Gods,” has scattered the colours of her rainbow staircase “wherever the rainbow ends,” be it lakeside or desert sand, rocky height or river valley.
In mediaeval days superstition attributed to the roots the power to cure coughs, fits, snakebites, dropsy and anger; but flowers were still symbols, and Iris, the Fleur-de-lis of the French kings, was chosen as their symbol of adherence to the Christian faith.
Chemists still use the “Orris Root” for the sake of its faint violet perfume, and in Siberia and South Africa there are edible species.
The Iris, well named “the poor man’s orchid,” with its striking form and showy colouring, can be grown so freely and increases so rapidly, that it is one of the cheapest plants to cultivate. The family is grouped into two main divisions, the Bulbous and the Tuberous-rooted kinds.
The Bulbous-rooted Irises can be grown in sunny borders if planted September or October about 3-5 in. deep and 6 in. apart. They equally well adorn the deep pockets of the, or perhaps most satisfactorily flourish in the mixed border, where other foliage will hide their fading leaves when flowering time is over.
They can be left where they are, year after year, until over-crowding becomes acute. Weeding is the only attention necessary, as they stand well without staking. Most species are not too exacting in the matter of watering.
They are propagated by offsets removed in autumn.
Pot Culture of Bulbous Irises
Winter-flowering Irises, such as I. tingitana and I. reticulata can be cultivated in pots, as also can the Spanish and English groups. Theshould consist of equal parts of loam, leaf-mould and silver sand (not forgetting drainage). A cold frame is best until top growth appears, then a cool greenhouse; forcing is unprofitable.
Water treatment is important. The soil should be moist at the time of potting, and remain unwatered until growth has commenced. Then water is given fairly freely until the flowers fade, after which very sparing quantities are needed.
As the main object of these greenhouse varieties is to provide household beauty for winter months, it is convenient to note that I. alata and I. reticulata, the sweet scented, can both be grown for Christmas, though the latter needs forcing, as it is a March-flowering species outdoors. I. pavonia, the Peacock-flowered Iris, is another variety suitable for pot culture.
Of the hardy outdoor bulbous Irises, the following are useful for the home garden: English Iris (”King of the Blues” and “White Lady”), Dutch Iris, Spanish Iris (”Gold Cup” and “Royal Blue”), I. bucharica, I. Juncea and I. sisyrinchium (which favours stiff soil).
Japanese Irises (I. Kaempferi). Unlike the bulbous plants, the Japanese Irises are water-lovers, and are best suited to the sides of informal pools, or anywhere where the soil is rich, loamy, moist and boggy. They should be planted in October or March, and during the growing season they will flourish better with the help of frequent doses of liquid manure. A sunny spot is preferable to one with too much shade.
The Herbaceous or Rhizomalous Irises include (1) Bearded. (2) Beardless and (3) Cushion Irises.
Bearded Irises have their outer falls or petals beautifully crested. They are the popular JUNE IRISES (I. germanica and hybrids), and are easily reared. No other flower of equal beauty is so “foolproof,” nor so easy to grow. Indeed, old gardeners sometimes say “let the man who cannot grow the Iris, stick to Aspidistras.”
The bearded Iris is increased by pieces broken off the thick rootstock, together with a few of the fibrous roots, and replanted in any ordinary soil containing some lime. A position in full sunshine is needed. The rootstock loves to lie in the sun and bake, so that the shallowest of planting is necessary, only the fibrous roots needing to be buried.
In breaking up the rootstock, choose the newest portions to replant, and see that each has its eye or growing point. Lift every two years as; with these prolific growers, overcrowding soon causes deterioration.
The Common Flag, is the best known of the Bearded Irises, but there are almost numberless hybrids now on the market which will repay a trial.
Beardless Irises. This group can be planted in October or March and prefers heavy rich soil usually, though some, such as the little American dwarf I. vertia prefer an acid diet, and thrive best in a peaty loam.
A few, notably I. sibirica, I. Ochroleicca and I. pseudacorus need moist soil, and are happy on the margins of ponds or streams, but a spot in the sun in either border or rockery is desirable for the majority.(unguicularis), is grown out-doors most successfully under a south wall In the cool greenhouse it blooms in mid-winter, and it will do the same in the open if the weather is mild. If not, it must be cut and brought indoors to open. A top dressing of gravel or chips is much appreciated in the damp days of winter.
Cushion Irises require more care and attention than other varieties. In a raised bed, against a South wall, prepare some light, rich loam mixed with mortar rubble. Plant in October, and protect the young plants with cloches or a cold frame during winter.
In July, lift the roots and store in dry sand in a warm shed or greenhouse until October, when they will be replanted. They are not so showy as bearded Irises, but are most interesting, and grow well in a bed made up of fertile river-sand.
Nearly all irises can be raised from seed sown in sandy soil in a cold frame, as soon as it is ripe. Sphagnum moss is laid over the sand to retain moisture while the seeds germinate.
The young shoots are fine like grass and transplanting is a work of care and patience. They may flower the second year but some kinds wait several years before they bloom.
Irises for specific purposes
A landscape gardener working for a sweep of colour as seen from a distance, rather than for individual beauty of form and shading, will naturally choose his varieties accordingly. Depth and evenness of colour, and clean design, are to him very important. Japanese Irises fulfil these conditions exactly, giving a wonderfully solid surface of rich colour. And certain of the bearded Irises (Othello for instance), though insignificant seen as single specimens, are very impressive en masse.
Irises for the Rock Garden are of course very much smaller, and for this purpose the race of Dwarf Bearded Iris comes into its own. These plants flower with the early violet and primrose, and do not cease until mid-May. Most of the hybrids are derived from I. pumila and I. chamesris—they have a sweet fragrance and a wide range of colours from pale yellow to lilac, blue-purple and dark red. In height usually 4-9 in., and rapid spreaders, they are useful also as plants for the Mixed Border.