How to grow iris

Irises are loved for their sumptuous, colourful, and beautifully marked flowers. The Iris genus comprises a wide range of types that can be grown in a variety of locations, from pond margins and damp soil to borders, banks, pots and rockeries. Iris is the name of the Greek goddess of the rainbow and, aptly, iris flowers offer a wonderful spectrum of colours.

Iris flowers also have a long association with French and English royalty, thanks to the Fleur-de-Lis symbol. Grown in the right spot, irises are easy to grow and long-lived. Most iris flowers bloom in summer, apart from the earliest bulbous types, such as Iris reticulata, which flower in early spring.



Bulbous irises are lovely for bursts of seasonal colour, though their flowers last for a short time only, before they die back and return to dormancy. Popular bulbous irises include Iris danfordiae and Iris reticulata, which bloom as early as February, bearing exquisitely marked blooms on 10cm stems. Brightly coloured Dutch iris is sold as a cut flower and, when planted in gardens, blooms in summer, producing large flowers on tall, sturdy stems.

Border irises include bearded iris (Iris germanica) and Siberian iris (Iris sibirica). As their name suggests, they’re ideal for growing in borders. Bearded iris is by far the largest group and is derived from species found in Mediterranean and Middle East regions, thriving in dry conditions.

Siberian iris grow well in any reasonable soil. Both types bear showy flowers on stout, upright stems. Bearded iris is so called for the caterpillar-like line of hairs on their lower petals.

Several flowers are borne on each sturdy, branched stem above clumps of sword-shaped grey-green leaves. These irises are sub-divided into groups: miniature dwarf, standard dwarf, intermediate, border, miniature tall and tall.Moisture-loving iris are hardy perennials with colourful blooms in late spring and early summer, bearing flowers on tall, stout stems above clumps of sword-shaped leaves.

They need soil that stays moist and doesn’t dry out at any time of year, but particularly in summer. These iris are best for growing in the margins of ponds, and bog gardens. The most popular species of moisture-loving iris are Iris ensata, Iris laevigata and the yellow flag iris, Iris pseudacorus.

How to grow irisesThe majority of irises grow best in a sunny spot in well-drained soil, apart from moisture-loving irises such as Iris sibirica, which need damp ground to thrive.Where to grow irises[image id="79157" size="landscape_thumbnail" title="Yellow flag iris, Iris pseudacorus. Jason Ingram" alt="Yellow flag iris, Iris pseudacorus.

Jason Ingram" classes=""] Yellow flag iris, Iris pseudacorus. Jason IngramBulb iris need full sun and must have well drained soil or the bulbs can rot. Grow larger bulb iris in border.

Miniature iris are ideal for containers.Border irises need full sun and free-draining soil, as the thick root is a water-storing device. Iris sibirica can tolerate a bit more shade than Iris germanica.

Grow moisture-loving irises in permanently damp soil, bog gardens, or in shallow water at pond edges.When to plant irisesIrises flower between spring and summer depending on the variety. Miniature irises such as Iris reticulata flower in spring, between February and March.

Iris sibirica flowers July to August and bearded irises flower between May and June.Plant iris bulbs (bulbous irises) in autumn, typically from September to November in the UK. Some bulbous irises (such as Iris reticulata) flower as early as February, so it’s important to plant them in good time otherwise they will flower late.

Don’t worry too much if you plant your iris bulbs later than November, as long as the bulbs are firm and show no signs of mould they will still grow, they will just flower later than they’re supposed to.Plant border irises from late summer to autumn, or spring.Plant moisture-loving irises in spring, summer, or autumn.

How to plant irisesIrises are bulbous perennials so will come back every year. The planting method varies, depending on the type of iris you are planting.Plant bearded iris so the top half of the fleshy root, or rhizome, is above ground and exposed to sun.

Space the rhizomes around 30cm apart.Iris sibirica should be planted with the top of the rootball at ground level.Plant miniature iris bulbs in containers, rockeries or borders.

In borders they can be planted deeper than in container, around 15cm deep, to ensure repeat flowering the following year.How to grow irises in pots[image id="98844" size="landscape_thumbnail" title="Planting Iris reticulata. Marsha Arnold" alt="Planting Iris reticulata.

Marsha Arnold" classes=""] Planting Iris reticulata. Marsha ArnoldPlant iris bulbs of dwarf iris such as Iris reticulata, in pots either outdoors or under protection in a greenhouse or a cool well-lit room. Fill a pot almost to the top with peat-free multi-purpose compost.

Plant bulbs, with the pointed end facing up, 5-7cm deep and around 10cm deep. Cover with compost and add a layer of grit to improve drainage.How to care for irisesAllow leaves of bulbous irises to die back naturally so the bulb can build up energy for next year.

Ensure iris bulbs don’t get too wet, particularly in winter, which can cause rotting.Bearded iris are long-lived but flowering declines once clumps become older and congested. Rejuvenate them by dividing and replanting the younger, outer parts of the clump in late summer, discarding the older pieces of root.

Divide large clumps of moisture-loving iris in late summer.Cut back irises after flowering, removing the flower stem at its base, but leaving the foliage to die down naturallyHow to take iris cuttings[image id="223125" size="landscape_thumbnail" title="Cutting off the top of iris leaves. Sarah Cuttle" alt="Cutting off the top of iris leaves.

Sarah Cuttle" classes=""] Cutting off the top of iris leaves. Sarah CuttleTo take iris cuttings, first dig up a clump of iris. Carefully split the rhizomes, either pulling them apart by hand or using a knife to separate them.

Try to separate them into pieces that each have leaves and a rhizome (underground stem). Reduce the leaves by half using a pair of clean secateurs.How to propagate irises[image id="223122" size="landscape_thumbnail" title="Dividing and replanting iris.

Sarah Cuttle" alt="Dividing and replanting iris. Sarah Cuttle" classes=""] Dividing and replanting iris. Sarah CuttleReplant each section around 12cm apart.

Don’t bury the rhizomes too deep as they need to be baked by the sun to flower well.Pests and diseasesIrises are affected by a number of diseases caused by bacteria and fungi. Some affect the leaves while others affect the plant below the soil, including the bulbs and rhizomes.

Leaf spot is most commonly found in bearded iris, and shows as small spots on the leaves with a brown or yellow margin. Remove infected leaves at the end of the season and burn them.Ink disease typically affects bulbous iris, and appears as black blotches on the leaves.

Plants affected by ink disease should be removed and destroyed (not in the compost), and avoid growing irises in the same spot for several years.Rust affects both bulbous and rhizomatous irises. Removing affected leaves can slow down the spread of the disease, but take care not to remove all leaves as this can affect the growth of the iris.

Advice on buying irisesMake sure you’re buying the right iris for your planting location. There’s no point in buying a bearded iris to grow around a pond or a moisture-loving iris for a dry, sunny border. Choose carefully and your iris will last for yearsIrises are available to buy from garden centres but you’ll find a wider range at specialist nurseriesWhere to buy irisesThompson & MorganVan MeuwenSuttonsWoottens Plants 10 Irises to growBorder iris:Iris ‘Edith Wolford’[image id="58966" size="landscape_thumbnail" title="Iris 'Edith Wolford'.

Paul Debois" alt="Iris 'Edith Wolford'. Paul Debois" classes=""] Iris ‘Edith Wolford’. Paul DeboisIris ‘Edith Wolford’ is a bearded iris with bright yellow standards and violet, ruffled falls.

It’s perfect for growing in a mixed herbaceous border or gravel garden.H x S: 90cm x 20cmBuy Iris ‘Edith Wolford’ from Thompson & MorganIris ‘Feu du Ciel’[image id="67537" size="landscape_thumbnail" title="Iris 'Feu du Ciel'. Jason Ingram" alt="Iris 'Feu du Ciel'.

Jason Ingram" classes=""] Iris ‘Feu du Ciel’. Jason IngramIris ‘Feu Du Ciel’ is a bearded iris that bears orange-yellow standards and falls with a darker orange beard, in contrast with green-grey, sword-shaped leaves.H x S: 80cm x 20cmBuy Iris ‘Feu du Ciel’ from irises.

co.ukIris ‘Wonders Never Cease’[image id="26198" size="landscape_thumbnail" title="Cream and brown iris 'Wonders Never Cease'. Jason Ingram" alt="Cream and brown iris 'Wonders Never Cease'" classes=""] Cream and brown iris ‘Wonders Never Cease’.

Jason IngramIris ‘Wonders Never Cease’ bears pretty flowers with white standard petals and white-edged bronze fall petals with a bright yellow beard, on slender stems.H x S: 80cm x 45cmBuy Iris ‘Wonders Never Cease’ from J Parker’sSiberian iris ‘Blue King’Siberian flag iris, Iris sibirica, produces small, delicate flowers and narrow, bright green foliage. Flower petals are purple with white and yellow markings.

Iris sibirica ‘Blue King’ bears deep violet flowers with veined yellow throats.H x S: 1.2m x 80cmBuy Iris sibirica ‘Blue King’ from BurncooseBulbous iris:Iris reticulata[image id="29410" size="landscape_thumbnail" title="Iris reticulata.

Jason Ingram" alt="Iris reticulata. Jason Ingram" classes=""] Iris reticulata. Jason IngramIris reticulata is an early flowering iris, bearing pale blue to deep violet blooms with central yellow splashes down the middle of each petal, from late winter to early spring.

H x S: 15cm x 10cmBuy Iris reticulata from CrocusIris reticulata ‘Katharine Hodgkin’ [image id="101097" size="landscape_thumbnail" title="Iris 'Katharine Hodgkin'. Sarah Cuttle" alt="Iris 'Katharine Hodgkin'. Sarah Cuttle" classes=""] Iris ‘Katharine Hodgkin’.

Sarah CuttleIris reticulata ‘Katharine Hodgkin’ has larger flowers than most other dwarf irises. Each creamy white bloom is covered with distinctive blue veining.H x S: 15cm x 10cmBuy Iris reticulata ‘Katharine Hodgkin’ from CrocusWinter iris, Iris histrioides[image id="54861" size="landscape_thumbnail" title="Iris histrioides.

Marsha Arnold" alt="Iris histrioides. Marsha Arnold" classes=""] Iris histrioides. Marsha ArnoldIris histrioides is a dwarf, bulbous iris bearing deep purple flowers with yellow markings, from late-winter.

Perfect for winter pot displays.H x S: 15cm x 10cmBuy Iris histrioides from HayloftYellow flag iris[image id="44226" size="landscape_thumbnail" title="Yellow flag iris, Iris pseudacorus. Jason Ingram" alt="Yellow flag iris, Iris pseudacorus.

Jason Ingram" classes=""] Yellow flag iris, Iris pseudacorus. Jason IngramYellow flag iris, Iris pseudacorus, is a vigorous water iris, typically found growing at the edges of large, sunny ponds. It bears large clumps of green leaves from which elegant, yellow flowers appear in late-spring.

H x S: 1.2m x 1mBuy yellow flag iris from CrocusStinking iris, Iris foetidissima[image id="46964" size="landscape_thumbnail" title="Stinking iris, Iris foetidissima. Jason Ingram" alt="Stinking iris, Iris foetidissima.

Jason Ingram" classes=""] Stinking iris, Iris foetidissima. Jason IngramIris foetidissima is the perfect iris for a shady spot, particularly beneath trees, where other plants struggle. It has architectural evergreen foliage and dull purple flowers, but it comes into its own in autumn when its large seedpods split open to reveal rows of orange-red seeds that remain well into winter.

H x S: 75cm x 45cmBuy Iris foetidissima from Claire AustinJapanese water iris, Iris ensata[image id="112324" size="landscape_thumbnail" title="Japanese water iris, Iris ensata. Sarah Cuttle" alt="Japanese water iris, Iris ensata. Sarah Cuttle" classes=""] Japanese water iris, Iris ensata.

Sarah CuttleJapanese water iris, Iris ensata, has variegated foliage and rich purple flowers. Perfect for growing at the pond edge, it will gradually spread to form a large clump.H x S: 75cm x 50cmBuy Iris ensata from CrocusFrequently asked questionsWhat should you do with irises after they bloom in the UK?After irises have flowered, you can deadhead them to make the plant look tidy, but let the foliage die down naturally as this provides energy for the plant.

In the autumn or spring, cut back dead foliage to ground level. If bearded iris clumps are overcrowded, divide these around six weeks after flowering.What is special about the iris flower?The iris has had significant meaning in many cultures throughout the ages, including the Ancient Egyptians who saw it as a symbol of victory and in Greece, where Iris is represented in Greek mythology.

In Medieval times, it was used as a charm to keep away evil..