Large Wild Iris Plant Care
Dietes grandiflora N.E.Br.
Updated · Sources · How we source care data
Dietes grandiflora, commonly named fortnight lily, large wild iris, African iris or fairy iris, is a rhizomatous perennial plant of the Iris Family (Iridaceae) with long, rigid, sword-like green leaves. This species is common in horticulture in its native South Africa, where it is often used in public gardens, beautification of commercial premises and along roadsides.
Every 7–10 days
Full sun to partial shade
50–85°F
40–70%
At a glance
How do you care for Large Wild Iris?
Water Large Wild Iris every 7–10 days, letting the top layer of soil dry out between waterings, and give it full sun to partial shade. It prefers temperatures of 50–85°F (10–29°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
What Is the Large Wild Iris?
Large Wild Iris (Dietes grandiflora) belongs to the Iridaceae family within the Dietes genus. Large Wild Iris is also known as Fortnight Lily, African Iris.
Large Wild Iris displays a clumping perennial growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Large Wild Iris produces white iris-like flowers with yellow and blue markings.
Leaf size: approximately 18 inches.
How Often Should You Water a Large Wild Iris?
Dietes grandiflora requires watering every 7–10 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 7–10 days
Let soil partially dry between waterings
What Light Does the Large Wild Iris Need?
Large Wild Iris thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Large Wild Iris Prefer?
Dietes grandiflora grows best at temperatures of 50–85°F. Large Wild Iris prefers humidity levels of 40–70%.
Temperature
50–85°F
Humidity
40–70%
What Soil Mix Works Best for a Large Wild Iris?
Well-draining sandy soil with added compost for extra nutrients. Good drainage is essential for Large Wild Iris to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Large Wild Iris?
Feed Large Wild Iris every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Large Wild Iris?
Repot every 2-3 years in spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Large Wild Iris?
Large Wild Iris can be propagated through division of rhizomes, seeds. Similar propagation techniques also apply to african iris plant care, which shares the same genus.
Is the Large Wild Iris Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Large Wild Iris, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Large Wild Iris?
Large Wild Iris is susceptible to aphids, spider mites. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Large Wild Iris Need?
Large Wild Iris grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. In cooler regions, grow Large Wild Iris as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Large Wild Iris is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Dietes genus — compare its care with other Dietes species on PlantoScan.
Dietes is part of the Iridaceae plant family — browse all Iridaceae genera and species.
Large Wild Iris thrives in bright light and direct sun — see other bright-light plants.
Related Plant Care Guides
Closely related plants with similar care requirements:
Sources
- Scientific name & taxonomy: Dietes grandiflora N.E.Br., family Iridaceae (first published in J. Linn. Soc., Bot. 48: 35 (1928)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Large Wild Iris, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
Identify Plants Like the
Large Wild Iris Instantly
Scan any plant with your phone camera and get instant ID, care tips, water and fertilizer reminders, and health checks — all in one app.
Free
to download
iOS & Android
platforms
Light & dark
mode
100,000+
species