Photo: Kevin FaccendaCC BY 4.0via iNaturalistresized / cropped
King grass Plant Care
Ischaemum polystachyum J.Presl
Updated · Sources · How we source care data
This plant is characterized by its striking, sword-shaped leaves with a central midrib. Hailing from tropical regions in Asia, Ischaemum polystachyum is highly sought after by plant collectors for its unique foliage that adds a tropical touch to any indoor jungle.
Every 3–7 days
Full sun to partial shade
60–85°F
40–70%
At a glance
How do you care for King grass?
Water King grass every 3–7 days, letting the top layer of soil dry out between waterings, and give it full sun to partial shade. It prefers temperatures of 60–85°F (16–29°C) and 40–70% humidity. Fertilize it every 8 months during the growing season.
Where Is the King grass Native To?
What Is the King grass?
King grass (Ischaemum polystachyum) belongs to the Poaceae family within the Ischaemum genus. King grass is native to New Guinea and the Pacific Islands. King grass is also known as African feathergrass, African foxtail grass.
King grass displays a clumping grass growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. King grass produces small inconspicuous flowers in spikelets.
Leaf size: approximately 12 inches.
How Often Should You Water a King grass?
Ischaemum polystachyum requires watering every 3–7 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 3–7 days
Let soil partially dry between waterings
What Light Does the King grass Need?
King grass thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the King grass Prefer?
Ischaemum polystachyum grows best at temperatures of 60–85°F. King grass prefers humidity levels of 40–70%.
Temperature
60–85°F
Humidity
40–70%
What Soil Mix Works Best for a King grass?
Well-draining loamy soil with added compost for nutrients. Good drainage is essential for King grass to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a King grass?
Feed King grass every 8 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 8 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 King grass?
Repot every 1-2 years in early 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 King grass?
King grass can be propagated through division, seeds. Similar propagation techniques also apply to coastal plains bluestem plant care, which shares the same genus.
Is the King grass Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list King grass, 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 King grass?
King grass is susceptible to aphids, grasshoppers, armyworms. 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 King grass Need?
King grass grows outdoors in USDA Zone 10b – 12b. It survives winters down to planting zone 10b. King grass is native to New Guinea and the Pacific Islands. In cooler regions, grow King grass as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 10b – 12b
Keep exploring plants
King grass 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 Ischaemum genus — compare its care with other Ischaemum species on PlantoScan.
Ischaemum is part of the Poaceae plant family — browse all Poaceae genera and species.
King grass 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: Ischaemum polystachyum J.Presl, family Poaceae (first published in Reliq. Haenk. 1: 328 (1830)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list King grass, 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.
- Photo: Kevin Faccenda, CC BY 4.0, iNaturalist — original.
- Hardiness zone: USDA Zone 10b – 12b, estimated from the plant's typical growing conditions.
- 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.
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