Tall Flatsedge Plant Care
Cyperus ustulatus A.Rich.
Updated · Sources · How we source care data
Cyperus ustulatus, also known as giant umbrella-sedge or coastal cutty grass is a species of sedge native to New Zealand. C.
Every 3–5 days
Bright indirect light
60–80°F
50–70%
At a glance
How do you care for Tall Flatsedge?
Water Tall Flatsedge every 3–5 days, letting the top layer of soil dry out between waterings, and give it bright indirect light. It prefers temperatures of 60–80°F (16–27°C) and 50–70% humidity. Fertilize it every 6 months during the growing season.
Where Is the Tall Flatsedge Native To?
What Is the Tall Flatsedge?
Tall Flatsedge (Cyperus ustulatus) belongs to the Cyperaceae family within the Cyperus genus. Tall Flatsedge is native to New Zealand.
Tall Flatsedge displays a grassy, clumping perennial growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Tall Flatsedge produces small, inconspicuous flowers in clusters.
Leaf size: approximately 12 inches.
How Often Should You Water a Tall Flatsedge?
Cyperus ustulatus requires watering every 3–5 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 3–5 days
Let soil partially dry between waterings
What Light Does the Tall Flatsedge Need?
Tall Flatsedge thrives in bright indirect light. Avoid placing Tall Flatsedge in direct, harsh sunlight for extended periods, as this can scorch the foliage.
Light Requirement
Bright indirect light
What Temperature and Humidity Does the Tall Flatsedge Prefer?
Cyperus ustulatus grows best at temperatures of 60–80°F. Tall Flatsedge prefers humidity levels of 50–70%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
60–80°F
Humidity
50–70%
What Soil Mix Works Best for a Tall Flatsedge?
Rich, moist soil with good drainage. Good drainage is essential for Tall Flatsedge to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Tall Flatsedge?
Feed Tall Flatsedge 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 Tall Flatsedge?
Repot every 1-2 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 Tall Flatsedge?
Tall Flatsedge can be propagated through division, seeds. Similar propagation techniques also apply to clustered flatsedge plant care, which shares the same genus.
Is the Tall Flatsedge Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Tall Flatsedge, 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 Tall Flatsedge?
Tall Flatsedge 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 Tall Flatsedge Need?
Tall Flatsedge grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. Tall Flatsedge is native to New Zealand. In cooler regions, grow Tall Flatsedge as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 13a
Keep exploring plants
Tall Flatsedge 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 Cyperus genus — compare its care with other Cyperus species on PlantoScan.
Cyperus is part of the Cyperaceae plant family — browse all Cyperaceae genera and species.
Tall Flatsedge thrives in bright light and direct sun — see other bright-light plants.
More Cyperus Species
Other Cyperus species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Cyperus ustulatus A.Rich., family Cyperaceae (first published in Voy. Astrolabe 1: 101 (1832)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Tall Flatsedge, 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 13a, 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.
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