No, it is a sedge, which is distinguished by its triangular stems.

Does it need full sun?

It prefers full sun but tolerates partial shade quite well.

Plant guide

Blue sedge.

Carex flacca

Pronounced KAIR-eks FLAK-uh

Also known as Glaucous Sedge, Heath sedge, blue sedge, blue-green sedge, carnation-grass

Carex flacca — Photo by Ondřej Křivan (CC BY) via gbif

This lovely sedge brings a cool, blue-green hue to your garden beds. It is a hardy, grass-like perennial that spreads slowly to form a nice groundcover. You will find it is quite adaptable to various soil conditions.

At a glance

Care level: Easy
Plant type: Perennial sedge
Light: Full sun to partial shade
Indoor light: Bright indirect
Water: Every 3 to 7 days
Mature size: 1 to 2 feet
Growth rate: Medium
Hardiness: USDA 4 to 9
Bloom time: Late spring to early summer

Care

Keep the soil consistently moist to mimic its natural wetland habitat. Watch for browning tips which often signal that the soil has dried out too much. You can trim back old foliage in late winter to make room for fresh spring growth.

Watering: Keep the soil evenly moist but not waterlogged.
Feeding: Apply a balanced, slow-release fertilizer once in early spring.
Pruning: Cut back dead or damaged foliage in late winter before new growth starts.
Repotting: Divide the clumps every few years to keep the plant vigorous.
Soil: Moist, well-draining soil
Soil pH: Slightly acidic to alkaline
Temperature: -25 to 30°C
Humidity: 40 to 70%
Drought tolerance: Moderate
Lifespan: Perennial, typically 5 to 10 years.
Deer and rabbits: High

Signs it needs repotting

Roots growing out of the drainage holes
Water sitting on the surface for too long
Reduced growth rate

Safety

People: There are no known toxic properties for humans.
Children: The foliage edges can be sharp, so keep it away from areas where small children play.
Contact allergens: The leaf edges can be sharp and may cause minor skin abrasions if handled roughly.
Airborne allergens: The pollen is wind-dispersed and may cause mild reactions in sensitive individuals.
Edibility: This plant is not intended for human consumption.

How to identify it

Powdery blue-green leaf blades
Arching, grass-like foliage habit
Slender, dark brown flower spikes
Forms dense, spreading clumps

Height: 0.2 to 0.4m
Spread: 0.3 to 0.6m
Leaves: blue-green, glaucous, evergreen
Flowers: brown, black, 1 to 3cm

Problems to watch for

Rust · Fungal spots may appear on leaves during periods of high humidity and poor airflow.

By symptom

Plant problems by symptom

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Growing it

Propagation: division, seed
When to plant: spring, autumn
Overwintering: It is evergreen and requires no special winter protection in most climates. Simply clear away any dead or damaged foliage in early spring.
In containers: It grows well in containers, provided the pot has good drainage and is at least 25 centimeters wide.

Division

1. Dig up the entire clump in early spring.
2. Use a sharp spade or knife to divide the root mass into smaller sections.
3. Replant the divisions immediately at the same depth as the original plant.

Plant in groups to create a dense mat that suppresses weeds effectively.

Grows well with

Hosta · The broad leaves of hostas contrast beautifully with the fine, blue-green texture of the sedge.
Coral Bells · These share similar light and moisture requirements while adding vibrant foliage colors.

Similar species

Gray Sedge · It has a similar clumping habit but features unique star-shaped seed heads.

Science

Family: Cyperaceae
Genus: Carex
Order: Poales
Class: Liliopsida
Native range: Europe and parts of North Africa.
Conservation: This species is widespread and not currently of conservation concern.

It grows in damp meadows and limestone grasslands, where it helps stabilize soil.

Value to wildlife: larval host plant, nesting material
Pollinators: bees, butterflies
Uses: groundcover, rock gardens, container filler, erosion control

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 3/9
Soil reaction: 7/9
Light: 6/9
Temperature: 5/9
Moisture: 6/9
Nutrients: 4/9

Taxonomy resolved against GBIF.

Questions people ask

Is it a true grass?: No, it is a sedge, which is distinguished by its triangular stems.
Does it need full sun?: It prefers full sun but tolerates partial shade quite well.

Where the name comes from

The genus name Carex comes from the Greek word for cutter, referring to the sharp leaf edges, while flacca refers to its drooping or flaccid appearance.

Good to know

It is commonly known as blue sedge due to its distinct foliage color.
It thrives in a wide range of soil types, including chalky or heavy clay soils.
The plant spreads slowly by rhizomes, making it a well-behaved groundcover.

Also in

Deer-resistant plants

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This guide was generated with AI on October 19, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.