

Graines de Dietes grandiflora - Iris des Fées
Dietes grandiflora - Fortnight lily
Dietes grandiflora
Fortnight lily, Large Wild Iris, Fairy Iris
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Nieves Del Volga A., 12/10/2018
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We guarantee the quality of our plants for a full growing cycle, and will replace at our expense any plant that fails to recover under normal climatic and planting conditions.
Seed-only orders are dispatched by sealed envelope. The delivery charge for seed-only orders is €3.90.

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Description
Dietes grandiflora, also known as African Iris, is also called Fairy Iris. It is a perennial evergreen rhizomatous plant with significant growth. It flowers from March to June, bearing numerous 10 cm (4in) diameter, white flowers with mauve and orange-yellow markings, above large clumps of sword-like leaves similar to irises. The flowers are short-lived, but many buds ensure their renewal. This somewhat tender plant likes humus-rich, well-drained soil, and full sun or partial shade.
The flowers appear from March to June in great numbers on tall flower spikes. They are relatively large and open into corollas with 6 petals, reaching about ten centimetres in diameter. The inner tepals are white, marked with orange-yellow spots in the centre. These spots are nectar guides, guiding pollinating insects towards food. The outer tepals and central segments are washed with violet. They only live for a few hours but are produced in large numbers. They are followed by an upright fruit, in the form of a 4 cm (2in) capsule that releases brown and shiny seeds.
The evergreen leaves are shiny, medium green, ribbon-like and sword-shaped, arranged in a fan, like garden irises. They can measure up to 1 m (3ft) long and 20 mm (1in) wide.
The large-flowered dietes is hardy to -7°C. Its cold resistance is directly linked to soil moisture. Under optimal conditions, it can withstand -10°C. For this reason, it can be planted in the ground in mild climate regions where it can form beautiful and very floriferous hedges. In colder areas, it is more often grown in large pots that it will quickly fill. This allows the plants to be stored in winter.
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Flowering
Foliage
Plant habit
Botanical data
Dietes
grandiflora
Iridaceae
Fortnight lily, Large Wild Iris, Fairy Iris
South Africa
Other Thompson and Morgan seeds
View all →Planting and care
The large-flowered dietes is easy to grow from fresh seeds, sown in spring which will germinate in warmth, in well-moistened soil.
Sow from February to April.
Dietes seeds germinate on the surface of well-draining seed compost. Cover the seeds with a very thin layer of soil or vermiculite. Maintain a temperature between 15 and 20 degrees (59 and 68°F) Celsius. Germination can take 1 to 3 months. Transplant the young plants when they are large enough to handle, into 8 cm (3in) diameter pots. They will need to spend the winter in a cool and well-lit room.
Plant the following spring, with a spacing of 90 cm (35in) between each plant.
Cultivation:
Choose a sunny exposure, neutral to acidic soil which is fertile but not excessively, to encourage flowering and moist but well-draining. Dietes grandiflora needs a lot of water in spring and summer. However, the soil should be well-draining. The plant will not tolerate soil moisture when it is cold, as this causes the rhizomes to rot. Its cold resistance is directly linked to soil drainage. Under good conditions, it can withstand -10 degrees (14°F) Celsius in fairly dry soil.
Sowing period
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Hardiness is the lowest winter temperature a plant can endure without suffering serious damage or even dying. However, hardiness is affected by location (a sheltered area, such as a patio), protection (winter cover) and soil type (hardiness is improved by well-drained soil).

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The flowering period indicated on our website applies to countries and regions located in USDA zone 8 (France, the United Kingdom, Ireland, the Netherlands, etc.)
It will vary according to where you live:
- In zones 9 to 10 (Italy, Spain, Greece, etc.), flowering will occur about 2 to 4 weeks earlier.
- In zones 6 to 7 (Germany, Poland, Slovenia, and lower mountainous regions), flowering will be delayed by 2 to 3 weeks.
- In zone 5 (Central Europe, Scandinavia), blooming will be delayed by 3 to 5 weeks.
In temperate climates, pruning of spring-flowering shrubs (forsythia, spireas, etc.) should be done just after flowering.
Pruning of summer-flowering shrubs (Indian Lilac, Perovskia, etc.) can be done in winter or spring.
In cold regions as well as with frost-sensitive plants, avoid pruning too early when severe frosts may still occur.
The planting period indicated on our website applies to countries and regions located in USDA zone 8 (France, United Kingdom, Ireland, Netherlands).
It will vary according to where you live:
- In Mediterranean zones (Marseille, Madrid, Milan, etc.), autumn and winter are the best planting periods.
- In continental zones (Strasbourg, Munich, Vienna, etc.), delay planting by 2 to 3 weeks in spring and bring it forward by 2 to 4 weeks in autumn.
- In mountainous regions (the Alps, Pyrenees, Carpathians, etc.), it is best to plant in late spring (May-June) or late summer (August-September).
The harvesting period indicated on our website applies to countries and regions in USDA zone 8 (France, England, Ireland, the Netherlands).
In colder areas (Scandinavia, Poland, Austria...) fruit and vegetable harvests are likely to be delayed by 3-4 weeks.
In warmer areas (Italy, Spain, Greece, etc.), harvesting will probably take place earlier, depending on weather conditions.
The sowing periods indicated on our website apply to countries and regions within USDA Zone 8 (France, UK, Ireland, Netherlands).
In colder areas (Scandinavia, Poland, Austria...), delay any outdoor sowing by 3-4 weeks, or sow under glass.
In warmer climes (Italy, Spain, Greece, etc.), bring outdoor sowing forward by a few weeks.