'As the Iris to the Bluebell, as the Heather to the Ling, As the Sunshine to the Twilight, so is Summer to the Spring.'
Alan B. Haig Brown.
I HAVE thought it best to deal with some of the Rhiizomatous Irises in this chapter, as well as with the Bulbous. After all, rhizomes can be broken into pieces for increase of stock, just as one detaches offsets from bulbs. And the inexperienced gardener (or perhaps 'semi-educated' would be the more suitable term) looks upon all Irises as bulbous plants, so would miss the 'Germans,' etc., and wonder what had become of them. No critic will be so captious, I hope, as to dislike a well-cultivated bulb garden because there are rhizomes, corms, or tubers in it as well as positive bulbs.
Some Irises require sunshine combined with ample moisture, conditions often offered by water-margins and bogs; or these will succeed in deeply built rockeries, where crags and slabs so shelter the soil as to keep it from drying at base.
Many of the rhizomatous, as distinct from the bulbous Irisesv- notably German Irisesi - make handsome pot and tub plants, but should not be planted lower than just below the soil, which will not require peat; also they are best sunk in their pots in cinder beds out of doors.
The depth to plant Iris rhizomes or bulbs, out of doors, will vary according to their size and the situa-tion. Three inches deep is a good average. In very light sandy borders a greater depth is often desirable: in wet, claggy ground rhizomes are usually placed only just below the surface. Spanish Irises and the winter-blooming Irises will grow and bloom in moss-fibre and sea-shell, in china bowls without drainage.
It is surprising how few persons grow the winter Irises in window-boxes, pots on window-sills, or in ornamental garden urns. A show of flower may be kept up from November to April, by combining Irises Alata, Stylosa-speciosa, Reticulata, and Histrio. They associate beautifully with Winter Crocuses (see Chapter VI (Snowdrops, Crocuses, Bluebells, Chionodoxas, Etc)), Christmas Roses, Snowdrops, yellow Winter Aconites and Hepaticas.
Most Irises should remain in beds or borders untouched as to roots until they are seen to be weakening, when lifting, division, and replanting elsewhere, or in renewed soil in the same place, should be undertaken. That is the great secret - prevent the roots of the bulbs and rhizomes from receiving any disturbance at other times. Mulching is safe; a layer of old cow-manure in October protects, or one in February stimulates.
Weak liquid manures can be given when buds are beginning to colour.
Seldom do we see properly grown German Irises, or any of the chief beauties of their family. Nine persons out of ten are, I believe, unaware that these Flags are ever anything but purple! A bed of the mauves, blues, brown terra-cottas, orange and gold, crimson-purple, and indescribably exquisite white and 'blends' might raise many a villa front garden far above the commonplace.
The Iris is very suitable for adorning roof gardens, in artificial or banked-up beds and borders, in rockery mounds, pots and tubs, and also in old wall pockets and simulated gutterings. Arrange for there to be 9 inches of soil for the roots, then the aperture or 'pocket' need not be wide. The Japanese Roof Iris, I. tectorum is best of all, in blue or white, but I have grown the January to March blossoming lavender-blue Iris stylosa in wall nooks, also the tiny species Iris Albiensis alba, white, known usually as a dwarf Crimean Iris, I believe, and the amethyst-blue Iris cristata.
If Spanish Irises were more mingled with other kinds of bulbs in front garden borders there would be no break in the flower-show between the late Narcissi and Tulips and the bedding-plants put out in June, or the host of herbaceous flowers that open during May and the following weeks would find themselves among graceful and beautifully coloured comrades.
It might well be recognized that Spanish and English Irises, the early white Florentine Iris, and some others, are plants that invalids may grow entirely in their rooms. The bulbs do not need to be hidden away in the dark or cinder-bed plunged, only to be kept cool, not dried up, yet not much watered, until growth starts: then any light airy place, out of direct sunshine, suits the plants; finally, the flower-table in the sunny window may hold them.
Innumerable lovely self shades and blends. Flowering in July and August.
The Gladwyn Iris. Brown-purple flowers, followed by pods bearing scarlet seeds, these being greatly valued for drying off for the winter vases. Will flourish also in semi-shade.
Yellow, tall. June and July.
The common Yellow Water Flag. Tall. May and June. There is a primrose variety, and a kind with silver-variegated foliage.
Siberian Irises are white or blue, or blue, cream and violet blends. They are often 4 feet tall, and make lovely masses during June and July.
The Japanese Roof Iris. Blue or white. Suitable also for dry borders and rockeries, but comes finest when in damp ground and full sunshine.
Bronze-red. June and July. Medium height.
Yellow and white ; a magnificent garden ornament.
Many a neglected, weedy, wet-soil garden could be transformed into a superb summer scene by the aid of Irises, such as the above, in the open positions, arranged in big groups, separated by 'carpet' spaces of Pansies, with Solomon's Seals and Daffodils for a spring effect among these, certain Liliums (see Chapter VII (Hardy Lilies, The Galtonia And Hardy Gladioli)) and Montbretias, with Meadow Saffrons beneath, for autumn. And the shady positions in wet gardens, those eye-offending puzzles, even the miserable end borders of slanted ground under deciduous trees, can have their fair flowers too.