<em>Ixia</em>: planting, cultivation and care

Botany

Ixias are perennial plants with corms that comprise just over 60 species. They originate from South Africa, which explains why they are not always very hardy. In the wild they grow mainly in open habitats, on sandy, very free-draining ground, sometimes in mountainous areas. In France, in the wild, one species has naturalized: Ixia dubia (on the Côte d’Azur, in Var… because climate there is mild enough for it!). Ixias have been cultivated in Europe since the mid-18th century. Many horticultural varieties now exist, offering a wide choice of flowering colours. They are geophytes that spend the unfavourable season underground as corms.

Ixias belong to family Iridaceae (more than 2,300 species), like iris, gladioli, Acidanthera, Crocosmia, or crocus. This family groups many ornamental plants, very decorative and often impressive for their flowering. Iridaceae are mainly rhizomatous, bulbous, or cormous plants, generally with long erect leaves with parallel veins, and flowers with six tepals and three stamens. They are valued for their elegant flowering and fine foliage. Ixias have a habit reminiscent of gladioli. Ixias are also closely related to Sparaxis, another iridaceous (the species Sparaxis tricolor is sometimes called Ixia tricolor).

The name Ixia comes from Greek iksia, meaning “glue”, because the sap of this plant is sticky. In French it is also called Lis des blés; in English, African corn lily.

Ixia viridiflora: botanical illustration

Ixias have very straight, rigid stems, giving them a very vertical habit. They range from 30–40 cm for the smallest varieties to 1 m for the tallest, with a few exceptions: Ixia acaulis, for example, is a small plant that grows and flowers at ground level with no evident stem.

Flowering takes place between May and August, depending on variety. The flowering period can vary slightly with climate and planting date. The plant then bears long, thin stems topped by spikes generally holding between 5 and 15 flowers. These are grouped fairly densely, making the display impressive.

The flowers are star-shaped, measuring between 3 and 8 cm in diameter. They are simple and elegant, without superfluous detail. Each flower is made up of six fused tepals (petals or sepals undifferentiated), oblong and regular in shape, forming a tube at the base. At the centre are three stamens bearing pollen and a style ending in three stigmas (female part that receives pollen). Flowers are pollinated, among others, by bees and by beetles.

They offer bright colours that catch the eye and bring energy to borders. Shades are tangy and vivid. Flowers may be pink, red, yellow, white, orange… They are often darker (sometimes almost black) at the centre, which gives them greater intensity and relief. Ixia viridiflora produces a surprising green–blue, turquoise tone — a truly unusual and very rare flowering colour. Ixia ‘Venus’ is striking for its flashy bright pink. The effect is very different between ixias with vivid pink, red or orange flowers, which bring much dynamism and attract attention, and those with white or cream flowers, which are delicate, graceful and can be integrated into romantic borders. The species Ixia ‘Spotlight’ has the particularity of outer petals marked with a pink line, adding an original touch of colour to its blooms.

Flowers of Ixia viridiflora (photo Jean-Michel Moullec), Ixia flexuosa (photo SAplants) and Ixia ‘Rose Emperor’

After flowering, Ixia produces oval capsules that split into three parts to release small brown seeds.

Ixias have attractive leaves, fairly narrow and elongated, linear. They are erect, straight and vertical, measuring between 10 and 60 cm long. They resemble grass leaves, but especially those of gladioli and other iridaceae. Veins are parallel and longitudinal. Leaves are arranged in a fan and are alternate, placed one after another. They are also sheathing, the base of the lamina surrounding the stem. They have a nice green colour.

Leaves are deciduous. They wither after flowering and reappear in spring. It is important to let them die back naturally and not cut them prematurely, because they allow the corm to accumulate nutrient reserves that will help it survive winter.

Ixia has corms. These are light brown–beige, pointed at the top, and bear roots underneath. They are underground storage organs that look a lot like bulbs but are not: they are flatter than bulbs and are formed of a swollen, hypertrophied stem protected by a tunic of dried leaves (scales). They allow the plant to store water and minerals to survive winter. After flowering the foliage of ixia dries off and the plant spends the winter underground as a corm, reappearing in spring when temperatures become milder.

Ixia corms: underground storage organs that resemble bulbs

Main varieties

Most popular varieties

Our favourite varieties

Ixia Venus - Corn lily

Essential variety, this superb Ixia offers very vivid, striking pink flowering! Use it to create a focal point in a border, or to add dynamism. The centre of the flower is slightly darker, but without a distinct macule.

• Flowering time July to September
• Height at maturity 40 cm

See the product sheet

Ixia Spotlight - Corn lily

This variety produces beautiful cream-white flowers, with the outer side of the tepals marked by a dark pink line, giving a delicate touch of colour. The centre of the flower is contrasted by a dark red macule. It is a rather romantic, luminous flowering.

• Flowering time July to September
• Height at maturity 50 cm

See the product sheet

Ixia Rose Emperor - Corn lily

This variety produces flowers of a softer pink than Ixia ‘Venus’. Flowers reveal lovely darker shades towards the centre.

• Flowering time July to September
• Height at maturity 50 cm

See the product sheet

 

Ixia Giant - Corn lily

This Ixia offers gentle, graceful flowering. In early summer it bears spikes of white flowers, marked at the centre by a black–deep purple macule.

• Flowering time July to September
• Height at maturity 50 cm

See the product sheet

Ixia Mix - Corn lily

This assortment of varieties will delight, offering a beautiful range of shades: mauve, pink, red, orange, yellow, cream-white... Ideal solution for a very colourful, bright border.

• Flowering time June to September
• Height at maturity 45 cm

See the product sheet

Planting

Where to plant?

Plant ixias in full sun! Good light is necessary for the development of their flowers. Ixia prefers rather warm, dry growing conditions and will do especially well in southern France.

Ixias prefer well-draining, permeable soil, because stagnant moisture can cause the corms to rot. Before planting, do not hesitate to add coarse sand or gravel to improve water infiltration into the soil. They also like fertile soil, rich in humus. You can add organic matter which will enrich the soil as it breaks down.

Ixias can easily be grown in pots or containers, in a free-draining compost. They will bring lots of colour and vitality to a sunny terrace or courtyard. In addition, pot culture makes it easy to bring them indoors for winter protection and then put them back out in spring. It is also possible to grow ixias under a greenhouse or in a conservatory, provided there is excellent light.

When to plant?

We recommend planting corms in spring, around April… But if you live in an area with a mild climate, for example in southern France, prefer planting from autumn (around October). Likewise, if you grow ixias in pots, you can plant in autumn and keep the pot under cover for winter.

How to plant?

For a more attractive display, we recommend planting ixias in groups rather than singly. Keep about 8 cm between corms.

For planting in open ground:

1. Choose location and, if necessary, add coarse sand or gravel.
2. Dig planting holes and place corms so they sit about 10 cm deep. Make sure they are positioned the right way up, point facing upwards. You can also place a thin layer of sand just beneath the bulb for drainage.
3. Cover with soil and firm down.
4. Water.

You can also plant ixias in pots:

1. Take a pot or container, place a drainage layer at the bottom (gravel, clay pebbles, pottery shards…), then add a free-draining compost (for example potting compost mixed with sand).
2. Plant corms, point facing upwards.
3. Cover with compost and firm lightly.
4. Water.
5. Place pot in full sun.

Care

You can water occasionally in spring and early summer, while plant is in growth and starting its flowering. Water a little more when flower buds appear, and stop watering as soon as foliage wilts, because ixias need soil to remain relatively dry during dormancy. If soil stays too wet, corms may rot. To encourage a good flowering, you can also apply some fertiliser in spring and early summer.

If you live in a cold region, it is preferable to lift and bring corms indoors for winter. Store them in a dry place. They will thus spend their dormancy protected from frost… You can replant them in spring, around April. Store them in same way as gladioli. If you live in a region with a mild climate and choose to leave corms in place in autumn, we nevertheless recommend applying a thick layer of mulch to protect them from cold.

During flowering, do not hesitate to cut flowers for bouquets. With their long, slender flower stems, ixias are ideal for arrangements.

We suggest regularly removing faded flowers. Besides aesthetic benefit, this encourages plant to produce new ones!

Do not cut foliage immediately after flowering; leave it in place, because it allows plant to rebuild reserves to get through winter. Wait for it to wither naturally before cutting it.

You can place a marker or label to remember their location and avoid damaging corms when working in the bed.

Sometimes taller varieties require staking to maintain an upright habit.

Ixias are rarely affected by diseases or parasitic pests. It can happen exceptionally that they are affected by mosaic virus, which discolours foliage. There is no treatment; affected plants must be removed.

Multiplication

Dividing corms

Easier than sowing, corm division is carried out in early autumn, when ixias are lifted and moved under cover.

1. Dig to lift ixia corms. Remove excess soil if necessary to make them clearly visible.
2. Separate them gently.
3. Place them under cover, in a dry spot protected from frost.
4. Wait until spring, around April, to replant them in open ground: work soil, add a little coarse sand if necessary, then plant them 10–12 cm deep, cover and water.

Sowing

They can be propagated by sowing. This operation is carried out in autumn, preferably using fresh seeds recently harvested.

1. Prepare a pot or seed tray, filling it with a free-draining substrate, for example a mix of potting compost and sand.
2. Scatter seeds on the surface.
3. Cover them with about 5 mm of sieved substrate, and firm lightly.
4. Water with a fine spray.
5. Place the pot in a bright position under a cold frame.

Depending on species, expect to wait two to three years before they flower.

Association

Ixias are perfect for composing a very colourful mixed-border, with many vivid flowerings. Typically, they combine very well with other Iridaceae, plants of the same family: gladioli, acidantheras, Iris germanica, crocosmias… They share an elegant, erect habit, fine foliage and an impressive flowering. In addition, these flowers are ideal for cutting to make bouquets! Ixias work very well with gladioli because they have the same cultivation requirements, are planted in the same way, and also overwinter similarly. Their flowers blend wonderfully! You can pair ixias with the superb, very natural flowering of Gladiolus italicus. Also enjoy the splendid, light and airy flowering of Cosmos! Also consider the flowers of dahlias. For a touch of originality, you can add a few Allium giganteum, with their large spherical purple inflorescences.

Ixias can be integrated into a border alongside colourful summer flowerings! Ixia ‘Spotlight’ / Dahlia x hortensis ‘Dahlietta’ (photo Harald Hoyer) / a scene with gladioli, dahlias and lilies (photo Steven Bemelman – iBulb) / Cosmos bipinnatus (photo Peak99) / Crocosmia

As ixias are available in a wide range of shades, you can easily play with colours to create varied effects, harmonies or contrasts. Use ixias, for example, to design a blazing bed in warm tones, with yellow, orange and red flowerings… Choose crocosmias, cannas, kniphofias, coreopsis, asclepias, rudbeckias… You can also add some dahlias. Add Pennisetum setaceum ‘Rubrum’, or Imperata cylindrica ‘Red Baron’. Also consider Eucomis for their exotic aspect. Discover too the impressive flowering of Eremurus, which carry long, very elegant upright flower spikes.

However, to avoid a border that is too overloaded in colour and visually “heavy”, do not hesitate to place small, lightweight flowers beside ixias, such as gypsophila and astrantias, or especially decorative foliage, such as ornamental grasses, ferns, acanthus, cardoons (Cynara cardunculus)… Choose large-leaved plants for a lush effect and to show off ixias’ flowering by creating a green setting that will make them stand out nicely… rather than drowning them in a mass of colours and flowerings!

Ixias with white, cream or soft pink flowers can easily fit into a romantic bed. Opt, for example, for the ‘Spotlight’ variety, which offers graceful white flowers with tepals shaded by a pink line. To accompany it, choose roses, gypsophila, lilies, hardy geraniums, clematis, Campanula lactiflora…

If you grow them in a pot, you can pair them with small, fairly low or trailing flowers, such as Bacopa or Lobelia. You can also choose pansies, verbenas, osteospermum, coreopsis… Create a composition that will bring lots of colour to your terrace or courtyard!

→ Discover other pairing ideas with Ixias in our advice sheet!