Great Fen-sedge Plant Care
Cladium mariscus Pohl
Updated · Sources · How we source care data
Cladium mariscus is a species of flowering plant in the sedge family known by the common names swamp sawgrass, great fen-sedge, saw-sedge or sawtooth sedge. Previously it was known as elk sedge.
Every 3–5 days
Full sun to part shade
60–85°F
50–70%
At a glance
How do you care for Great Fen-sedge?
Water Great Fen-sedge every 3–5 days, letting the top layer of soil dry out between waterings, and give it full sun to part shade. It prefers temperatures of 60–85°F (16–29°C) and 50–70% humidity. Fertilize it every 6 months during the growing season.
What Is the Great Fen-sedge?
Great Fen-sedge (Cladium mariscus) belongs to the Cyperaceae family within the Cladium genus. Great Fen-sedge is also known as Great Fen Sedge, Prickly Sawgrass, Prickly Saw-grass.
Great Fen-sedge displays a tall, grass-like growth habit, reaching up to 6 ft tall with a spread of approximately 3 ft. Great Fen-sedge produces small, inconspicuous flowers in terminal clusters.
Leaf size: approximately 18 inches.
How Often Should You Water a Great Fen-sedge?
Cladium mariscus 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 Great Fen-sedge Need?
Great Fen-sedge thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Great Fen-sedge Prefer?
Cladium mariscus grows best at temperatures of 60–85°F. Great Fen-sedge prefers humidity levels of 50–70%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
60–85°F
Humidity
50–70%
What Soil Mix Works Best for a Great Fen-sedge?
Rich, moist soil with high organic content. Good drainage is essential for Great Fen-sedge to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Great Fen-sedge?
Feed Great Fen-sedge 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 Great Fen-sedge?
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 Great Fen-sedge?
Great Fen-sedge can be propagated through division, seeds. Similar propagation techniques also apply to twayblade sawgrass plant care, which shares the same genus.
Is the Great Fen-sedge Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Great Fen-sedge, 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 Great Fen-sedge?
Great Fen-sedge is susceptible to aphids, scale insects, 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 Great Fen-sedge Need?
Great Fen-sedge grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. In cooler regions, grow Great Fen-sedge as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 13a
Keep exploring plants
Great Fen-sedge 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 Cladium genus — compare its care with other Cladium species on PlantoScan.
Cladium is part of the Cyperaceae plant family — browse all Cyperaceae genera and species.
Great Fen-sedge 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: Cladium mariscus Pohl, family Cyperaceae (first published in Tent. Fl. Bohem. 1: 32 (1809)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Great Fen-sedge, 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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