Rainbow-coloured bearded iris

Flowers of the many-coloured bearded iris put on a dazzling show, enhanced by ruffles, frills, lace and falls

billowing in the breeze like sailing ships, the blooms of bearded iris fill the early summer garden with all the colours of the rainbow. Their large flowers combine beauty of form and purity of shade, as well as a subtle, sweet perfume. Easily recognised, these majestic flowers offer a beauty unrivalled by any other hardy perennial. Growing from thickened horizontal stems, called rhizomes, bearded iris bloom as summer progresses, depending on the type. Carefully adapted to allow access for pollination by large bees, the flowers are remarkably complex. The three outer petals open wide and often droop at the tip. These are called falls. At the base of each is the furry beard, from which the name derives. This is usually showy and may be a different colour to the petals. The large, prominent inner three petals usually stand erect, and again are often a different colour. These are the standards. Above the three beards is a single stamen, and above that is one arm of the three-branched stigma. This is often showy and petal-like. On the underside, near the end, is the stigmatic flap that catches the pollen from a visiting insect, under the style crest, a conspicuous, petal-shaped appendage. Bearded iris are divided into different classes, based on size and flowering time. They range from miniatures to

the most widely planted, the Tall Bearded iris (TB). Reaching up to 40in (100cm) or more, these are the most dramatic. Peaking in late May and early June, they have seven or more blooms per stem. Their flowers are larger than all other types, with a great variety in shape and colour. Early types, such as ‘Deputé Nomblot’, have falls that hang down almost vertically. Today, modern varieties, such as ‘Paul Black’, have been bred for flaring, almost horizontal falls. Over the years, breeders have worked at developing thicker petals than those of the original wild species. This has led to bigger and longer-lasting garden flowers, better able to withstand sun and rain, as well as brighter colours. Lace is another feature of modern iris, where the petals are finely crinkled around the edges, such as ‘Lace Legacy’.

Developing new looks

The plants used to breed modern garden iris came from the Mediterranean area, and included blue-flowered Iris pallida. From the wild species, bearded iris developed only slowly until the early decades of the 20th century. Then, in the 1920s, Britain was at the forefront of iris breeding. Larger and brighter flowers were produced, some of which are still grown today. Violet ‘Deputé Nomblot’ was introduced in 1929. Three years later, it was described in the American Cooley’s garden catalogue as “the world’s greatest iris”. A year earlier, Cayeux’s ‘Pluie d’Or’ was the epitome of the yellow iris, described in the raiser’s catalogue as “the first large flowered iris deep yellow of actual value put into commerce”. Until the 1950s and ’60s, the new varieties had rather droopy falls. Then, in the 1950s, ruffling of the petals appeared. ‘Blue Rhythm’ is typical of iris from this era, with simple, lightly ruffled flowers. Today, hundreds of new iris are introduced every year. Most fade into obscurity, but a few stand the test of time, such as the curiously coloured chocolate and yellow TB ‘Provencal’ from 1978.

To survive, an iris needs more than beautiful flowers. Vigour and the number of buds also count. More buds on the stem mean more flowers and a longer season of bloom. Hardiness and a good name mean enduring fame.

Careful placement

Because of the range in sizes, bearded iris can be fitted into many parts of the garden. Miniature Dwarfs are suitable for pots and rock gardens. They can be swamped in general borders, where Standard Dwarfs are better, especially at the front. These are strong growers, also doing well in gravel and on rockeries. The bigger types are good in herbaceous borders, as long as they are not crowded out by bigger plants. Neighbours with upright or ferny foliage that does not cover the iris’ rhizomes are best. Aquilegias and lupins, which flower at the same time, make spectacular companions. When out of flower, the sword-like leaves of iris add interest, and fit well with minimal-style plantings. Roses are good companions too, if care is taken not to mulch over the base of the iris. Many modern varieties, such as ‘Lune et Soleil’, have horizontal falls and intriguing mixtures of colours. However, the hanging falls and simpler colours of the old cultivars tend to show up better in the garden from a distance. Their flaring falls also help reveal their beauty up close when viewed from above.

Cultivation

Bearded iris have two periods of root growth, in spring and in late summer. This is when they should be planted, with July and August ideal, giving them time to make roots before winter. Potted iris can be planted at any time, but those planted in spring may be unsteady when they produce their first flower stems. These should be staked.

They need a sunny site and well-drained alkaline, neutral or acid soil. It is essential that the rhizomes see the sun, so the ground should be kept free from weeds and other plants, and fallen leaves, at all times. The end of each rhizome flowers, and new sideshoots are produced behind this. After a few years, these will get crowded and need to be divided. How long this takes will depend on the variety, but most will need to be divided after four years. Overcrowded clumps do not flower well. To divide, the clump is dug up and split, cutting or snapping off the newest shoots with approximately 4in (10cm) of rhizome. This should be less for the smaller types. The foliage is trimmed back to approximately half its length, to reduce water loss and help prevent wind rock. The old pieces are discarded. The soil is dug over, with high-potash fertiliser added, such as rose fertiliser. The prepared pieces are planted 6-10in (15-25cm) apart, depending on the size of the variety. Ideally, they are arranged facing the same way, with the cut part of the rhizome pointing south. This helps prevent the leaves shading the rhizome. The rhizome is not covered with soil, which is pressed firmly around the roots to hold them steady. Deep planting, especially on heavy soil, causes rot. If it does not rain within two weeks of planting, the plants are given a soak. After that, they only need keeping free from weeds. A high-potash feed is beneficial in March/April, when they start to grow. At this time, some of the old leaves can be pulled or cut away to reduce rot and make them tidier. The new flower stems may need protecting from snails. To make the display tidier, the faded flowers can be broken off. Once all the flowers have died, the whole flower stem should be snapped off at the base, along with the adjoining leaves. With their intricate blooms and dazzling colour, bearded iris are a captivating addition to the garden, whether in borders or containers, and an elegant cut flower for the home. Their aversion to crowds ensures their singular beauty can be fully appreciated as they stand slender and proud in the early summer sunshine.

The curiously coloured plicata flowers of TB ‘Provencal’. With its bright yellow horizontal falls, ‘Lune et Soleil’ puts on a glowing display.

The falls of ‘Deputé Nomblot’ hang almost vertically down, while those of ‘Paul Black’ are almost horizontal (from left).

Standing tall, this hybrid iris has delicate blue falls and standards (top). The true species, Iris pallida, showing the furry beard which gives these iris their name (bottom). Standards Stamen Falls Stigma Crest Beard Falls

Bearded iris help add height to a colourful border display. When rhizomes are divided, they are replanted with the cut part facing south, above the soil. Some bearded iris, such as ‘Victoria Falls’, are known as remontant iris, flowering more than once...