Spanish iris

Spanish iris: how do you recognise it?

Habit

Upright bulbous plant about 50 cm tall and 10 cm wide, forming an airy clump in a group.

Leaves

Narrow, grass-like and grey-green; they die back after flowering, sometimes as early as July.

Flower

One to three flowers per stem in June; each flower is short-lived, but several open in succession.

Colour

Blue, purple, white or yellow, with a yellow blotch on the drooping petals.

Bulb

Oval bulb with a brown, fibrous coat; it forms new bulblets every year.

Flowering: June · Plants: September–October

Why grow it?

• Elegant flowers in June, in blue, purple, white or yellow, on upright stems above narrow leaves.
• An excellent cut flower: a few stems last several days in the vase.
• Drought tolerant: the bulb rests in a warm, dry summer and flowers again the following year.
• Bees visit the flowers and the plant needs little care.
• Suits a sunny border, a gravel garden or a large pot.

Spanish iris: where does it grow best?

• Full sun in a warm, sheltered spot; in shade it hardly flowers.
• Well-drained soil: sandy or loamy, lime is tolerated. Heavy, wet clay makes the bulb rot.
• Above all keep the soil dry in summer: it likes a warm, dry summer rest.
• Sheltered from strong wind; the stems are slender.
• Plant the bulbs 10–15 cm apart, in groups of at least 10.

Light

Sun

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry

Size

0.5 m tall, 0.1 m wide

Hardiness

Half hardy (to -10 °C): protect it in harsh winters

Goes well with

• Lavender: Same sunny, dry conditions, flowers at the same time.
• Sage: Blue-purple flowers next to the irises on free-draining soil.
• Ornamental grasses: Soft plumes fill the gap when the iris leaves die back.
• Catmint: Blue flowers and grey-green leaves go well with irises.

Spanish iris: when and how to plant it?

Plant in September–October.

1. Plant in September–October, as soon as you have the bulbs.
2. Dig a hole about 10 cm deep; mix heavy soil with coarse sand for better drainage.
3. Set the bulbs pointed end up, 10–15 cm apart.
4. Cover with soil and water only if the autumn is very dry.
5. In a cold area, spread a 5–10 cm layer of dry leaves or compost over the bulbs against frost.

Care

Water

In spring, while the leaves grow, rarely needed; water only in a long dry spell. During the summer rest keep the soil dry.

Feeding

In spring, a little bulb fertiliser or compost. Not too much nitrogen.

Mulching

A layer of coarse sand or fine grit keeps the bulb dry and the soil free-draining; in winter a thin layer of leaves or compost.

Spent flowers

Cut them off so that the bulb does not waste energy on seed.

Dividing

Divide crowded clumps after flowering every 3–4 years, when flowering declines.

Tip: It needs a warm, dry summer to flower again. Plant 10 cm deep in a sunny spot with light soil and leave the bulbs alone after flowering.

Spanish iris: when to prune it?

When: Pruning is not needed. Cut off spent flowers and remove the leaves only when they are yellow and withered, usually in July.

How:

• Cut the spent flower stem off just above the ground.
• Leave the leaves until they turn yellow; they feed the bulb for next year.
• Remove the withered leaves with sharp scissors.

Caution: Do not cut the green leaves too early, or the bulb will flower less next year.

Pruning calendar and basic rules

Propagation

Division

In July–August, when the leaves are yellow: lift the clump, separate the bulbs and replant them at once or in September at 10 cm deep.

Seed

Sow in autumn in a tray outdoors; seedlings take several years to flower. Division is much faster.

Spanish iris: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Hardy to about −10 °C: in Flanders usually safe, but in hard winters the bulbs can freeze.
• Protect the spot with a 5–10 cm layer of dry leaves, straw or compost and remove it in March.
• In a pot: keep the pot frost-free and dry, or against a wall with an insulating layer.

Diseases and pests

• Bulb rot: In wet, cold soil the bulbs rot and there is no flower. Plant in free-draining soil and mix clay with sand.
• Slugs: They eat young leaves in spring. Pick them off by hand in the evening.
• Mosaic virus: Light or dark streaks in the leaves, deformed flowers. There is no cure: remove the plant, use clean tools and control aphids.
• Frost damage: Frosted leaves in spring are not serious; the bulb simply sprouts again. Protect the bulbs in hard winters.

Through the year

• March: Leaves appear. Cover if there is hard frost.
• April: Remove the protective layer. Apply bulb fertiliser.
• May: Buds form.
• June: Flowering. Cut flowers for the vase.
• July: Leaves turn yellow. Lift and divide bulbs if needed.
• August: Summer rest. Keep dry.
• September: Plant, 10 cm deep.
• October: Plant. Lay dry leaves as protection.
• November: Last chance to plant.
• December: Resting underground.

Edible and useful

Not edible. All parts of these bulbous irises are poisonous, especially the bulb: eating any causes vomiting, stomach ache and diarrhoea, and dogs and cats fall ill from it too. In autumn the small bulbs look like shallots or onion sets: do not store them with the kitchen onions, plant them straight away and clear up empty bags and loose bulbs. Dogs that dig easily bring them up, and dwarf irises in a pot indoors are often at a child’s height. People who cut a lot of flowers or plant a lot of bulbs sometimes get red, itchy skin from the sap: wear gloves and wash your hands afterwards. If an animal has eaten some, call your vet. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The species name xiphium comes from the Greek xiphos, ‘sword’: a reference to the narrow, sword-shaped leaves.
• It is one of the parents of the Dutch iris, the bulbous irises you know as cut flowers.
• The bulb rests in summer and does not want to be too wet: exactly the conditions of its Mediterranean homeland.