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

Botany

Ixias are perennial plants with corms that include a little 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 soils, sometimes in mountainous areas. In France, in the wild, one species has naturalized, Ixia dubia (on the French Riviera, in the Var… as the 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. These are geophytes, which spend the unfavourable season underground as corms.

Ixias belong to the family Iridaceae (more than 2,300 species), like irises, gladioli, Acidanthera, Crocosmia, or crocuses. This family includes many ornamental plants, highly decorative and often impressive for their flowering. Iridaceae are mainly rhizomatous, bulbous, or cormous plants, which generally have long erect leaves with parallel veins, and flowers with six tepals and three stamens. They are appreciated for their elegant flowering and fine foliage. The habit of ixias actually recalls that of gladioli. Ixias are also close to Sparaxis, another iridaceous (the species Sparaxis tricolor is sometimes called Ixia tricolor).

The name Ixia comes from the 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 that give them a strongly vertical habit. They measure between 30–40 cm for the smallest varieties and up to 1 m for the tallest, with some exceptions: Ixia acaulis, for example, is a small plant that grows and flowers at ground level without an obvious stem.

Flowering occurs between May and August, depending on variety. The flowering period can vary slightly according to climate and planting date. The plant then bears long, thin stems topped by spikes usually holding between 5 and 15 flowers. These are grouped fairly densely, which makes the display striking.

The flowers are star-shaped, measuring between 3 and 8 cm in diameter. They are simple and elegant, without unnecessary detail. They consist of six fused tepals (petals or sepals indistinguishable), 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 will receive pollen). Flowers are pollinated, among others, by bees and by beetles (scarab beetles).

They offer vivid colours that catch the eye and bring dynamism to borders. Shades are tangy and bright. Flowers can be pink, red, yellow, white, orange… They are often darker (sometimes black) at the centre, giving more intensity and relief. Ixia viridiflora displays 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 differs greatly between ixias with vivid pink, red or orange flowers, which bring energy and attract attention, and those with white or cream flowers, which are delicate and graceful and can fit into romantic borders. The species Ixia ‘Spotlight’ is notable for the outer side of its petals being marked by a pink line, adding an original touch of colour to its flowering.

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, very straight and vertical. They measure between 10 and 60 cm in length. They resemble grass leaves, but especially those of gladioli and other iridaceae. Veins are parallel and longitudinal. Leaves are arranged in a fan and placed alternately, one after another. They are also sheathing, the base of the lamina surrounding the stem. They have a nice green colour.

The leaves are deciduous. They wither after flowering and re-emerge in spring. It is important to let them die back naturally and not cut them too early, because they allow the corm to accumulate nutrient reserves that will help it survive winter.

Ixia has corms. They are light brown–beige, pointed at the top, and bear roots underneath. These are underground storage organs that resemble bulbs but are not bulbs: they are flatter than bulbs and consist of a swollen, hypertrophied stem protected by a covering of dried leaves (scales). They allow the plant to store water and mineral elements to survive winter. After flowering, ixia foliage dries up 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

The most popular varieties

Our favourite varieties

Ixia Venus - Corn lily

A must-have variety, this superb Ixia offers very vivid, striking pink flowering. Use it to create a focal point in a border or to add dynamism. 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 creamy-white flowers, with the outer tepals marked by a dark pink line, adding a delicate touch of colour. Centre of the flower is contrasted by a dark red macule. It is a rather romantic and 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 at the centre.

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

See the product sheet

 

Ixia Giant - Corn lily

This Ixia offers a soft, 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 by offering a beautiful range of shades: mauve, pink, red, orange, yellow, creamy white... It is the ideal solution for a very colourful, luminous 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 their flowers to open. Ixia enjoys rather warm, dry growing conditions and does particularly well in southern France.

Ixias prefer free-draining, permeable soil, as standing moisture could cause the corms to rot. Before planting, feel free to add coarse sand or gravel to allow better infiltration of water 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 a pot or container, in a well-draining substrate. They will brighten a sunny terrace or courtyard, bringing lots of colour and vitality. Also, planting in a pot makes it easy to bring them in for winter to protect them from frost, then put them back out in spring. It is also possible to grow ixias in a greenhouse or conservatory, provided there is excellent light.

When to plant?

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

How to plant?

For best effect, we recommend planting ixias in groups rather than singly. Leave about 8 cm between corms.

For planting in open ground:

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

You can also plant ixias in a pot:

1. Take a pot or container, place a drainage layer at the bottom (gravel, clay balls, broken pot shards…), then add a well-draining substrate (for example compost mixed with sand).
2. Plant the corms, point upwards.
3. Cover with substrate and firm gently.
4. Water.
5. Make sure to position the pot in full sun.

Care

You can water occasionally in spring and early summer, while the plant is growing and beginning to flower. Water a little more when flower buds appear, and stop watering as soon as foliage wilts, because ixias need soil to remain relatively dry while in dormancy. Excess moisture can cause corms to rot. To encourage good flowering, you can also apply some fertiliser in spring and early summer.

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

During flowering, feel free to cut flowers for bouquets. With their long, slender flower stems, ixias are ideal for arrangements.

We suggest regularly removing faded flowers. As well as the aesthetic benefit, this encourages the plant to produce new ones!

Do not cut foliage immediately after flowering; leave it in place, as it allows the plant to rebuild its reserves for winter. Wait for it to wilt naturally before cutting it back.

You can place a marker or label to remember their location and avoid damaging corms if you work in the border.

Sometimes taller varieties need staking to maintain a straight, upright habit.

Ixias are rarely affected by diseases or parasitic organisms. They can occasionally be affected by mosaic virus, which depigments the foliage. There is no treatment; affected plants should be removed.

Multiplication

Corm division

Easier than sowing, division of corms is carried out in early autumn, when ixias are lifted to be put under cover.

1. Dig to lift ixia corms. Remove excess soil if necessary to make them clearly visible.
2. Separate them gently.
3. Keep them under cover, dry and protected from frost.
4. Wait until spring, around April, to replant in open ground: prepare soil, add coarse sand if required, then plant them 10 to 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 medium, for example a mix of potting compost and sand.
2. Scatter seeds on the surface.
3. Cover with about 5 mm of sieved compost, and firm lightly.
4. Water with a fine spray.
5. Place pot in a bright position, in a cold frame.

Depending on species, it will generally take two to three years to see them flower.

Association

Ixias are perfect for composing a very colourful mixed-border, with many vivid flowerings. Typically, they pair very well with other Iridaceae, plants of the same family: gladioli, acidantheras, Iris germanica, crocosmias… They share a very elegant, upright habit, fine foliage, and an impressive flowering. In addition, these flowers are ideal for cutting for bouquets! Ixias go very well with gladioli because they have the same cultivation type, the same requirements, are planted the same way, and also overwinter similarly. Their flowers blend wonderfully! You can combine 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 violet inflorescences.

Ixias can be integrated into a border alongside colourful summer blooms! 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

Because ixias come in a wide range of shades, you can easily play with colours and create varied effects, harmonies or contrasts. Use ixias, for example, to create a flamboyant border in warm tones with yellow, orange and red flowerings… Choose crocosmias, cannas, kniphofias, coreopsis, asclepias, rudbeckias… You can also include some dahlias. Add Pennisetum setaceum ‘Rubrum’, or Imperata cylindrica ‘Red Baron’. Also consider Eucomis for the exotic touch they bring. Discover too the impressive flowering of Eremurus, which bear long, very elegant erect flower spikes.

However, to avoid a border that is too overloaded with colour and visually “heavy”, don’t hesitate to place, alongside ixias, small delicate flowers, such as those of gypsophilas and astrances, or above all, decorative foliage, such as that of ornamental grasses, ferns, acanthus, cardoons (Cynara cardunculus)… Choose large-leaved plants for a lush effect and to showcase the flowering of ixias, creating a green backdrop 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 border. Opt for the variety ‘Spotlight’, which offers graceful white flowers with tepals shaded by a pink line. To accompany it, choose roses, gypsophilas, lilies, hardy geraniums, clematis, Campanula lactiflora…

If you grow them in pots, you can combine them with small, 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 ideas for pairing with Ixias in our care sheet!