How to Grow Iris Bulbs
There is probably noof flowers with such a wide variation of habit and extended colour range as that of the iris. It is not very difficult to obtain a colourful display for at least nine months of the year.
Dutch irises are strong growing with large flowers of great substance, blooming from the end of May onwards. They provide fine colour for the border and are also of great value for forcing, the varieties Wedgwood and Imperator being particularly suited for this purpose. The former grows about 2 ft. and has Wedgwood-blue standards with deeper blue falls. Valuable as a cut flower, Imperator has large lavender-purple standards and broad azure-blue falls with a brilliant yellow blotch. There are many more excellent varieties.
Spanish irises flower about the second week in June and there are many varieties. If the flower spikes are cut when in bud they will open and last a long time in water. Particularly good varieties include Bronze Queen; Cajanus, large canary yellow with orange blotch; La Nuit, dark violet standards and cobalt-blue falls with a yellow blotch; La Nuit, a really handsome flower with a violet-blue standard and a white fall which has a golden blotch. Thunderbolt, or The Great Bronze Iris, produces stately bronze flowers with large orange blotches.
Both Dutch and Spanish irises should be planted about 3 in. deep during September and October and they like an open sunny position with a lightish well-drained soil in which they will multiply rapidly and bloom freely, especially if the soil is given a dressing of bonemeal in the late autumn.
English irises grow 18 to 24 in. high and flower into July. Theshould be planted from October onwards. Cover with 3 in. of soil and provide a position which is moist, but by no means waterlogged.
Good varieties of English irises are Baron Von Humboldt, rosy lilac splashed and flaked ruby; King of the Blues; Mont Blanc, pure white; Princess Juliana, deep blue with yellow blotch; and Rosa Bonheur, white flaked rosy purple.
Where the soil is on the dry side, the Spanish and Dutch irises always thrive, while in heavier positions, the English varieties provide a charming display.
Few iris species equal the beauty and attractiveness of Iris reticulata which produces its colourful blooms in the dark days of February. Although very charming, it easily establishes itself and may be left in position for five or six years before the bulbs are lifted and divided. It has thin pointed foliage and theare a deep purple-violet each with a prominent yellow blotch on 9-in. stems. There are a number of excellent forms including Iris Cantab with delicate blue standards and pale violet-blue falls with a good crest; Royal Blue, a large-flowered, sweet-scented Oxford blue with a yellow blotch; Wentworth, purple-blue; and Hercules, bronze violet.
A position sheltered from strong winds should be selected, for these are liable to damage the early flowers and foliage. Goodis important for too much moisture at the roots will soon lead to disease. Groups of six or more give a much more pleasing effect than straight line planting. Iris danfordiae is very like Iris reticulata in shape but it is pure yellow and shows its flowers on 3-in. stems in February. Iris histrioides major has blue flowers from January to March.