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Carex lacustris
lake sedge
Carex lacustris
Carex lacustris, commonly known as lake sedge, is a large, cool-season sedge that thrives in wet, marshy areas. It forms dense clumps of upright, blue-green foliage, reaching heights of 2-4 feet. In late spring, it produces inconspicuous, brown flower spikes. It is an excellent choice for erosion control along shorelines and in rain gardens, providing habitat for wildlife.
CategoryDetails
Plant TypePerennial plant
Estimated Plant Lifespan5 years lifespan
Sun Requirements4-6 hours direct sunlight (Partial Sun)
Pollination

Method: wind

Watering Requirements

Frequency: Keep soil consistently moist

Notes: Tolerates standing water.

Humidity Requirements

Level: moderate

Care InstructionsRemove dead or brown foliage in early spring to promote new growth. Divide clumps every few years to maintain vigor and prevent overcrowding.
Temperature Range

Min: -30°C

Max: 35°C

Alternative Nameslakeside sedge, lake-bank sedge
Iris versicolor
northern blue flag
Iris versicolor
Both enjoy moist soil and similar light conditions, creating a visually appealing combination of textures and colors.
Asclepias incarnata
swamp milkweed
Asclepias incarnata
They share a preference for wet conditions and provide habitat and food sources for pollinators.
Typha latifolia
broadleaf cattail
Typha latifolia

Cattails are aggressive spreaders and can outcompete Carex lacustris for resources in wetland environments.

Phragmites australis
common reed
Phragmites australis

While some Phragmites cultivars are non-invasive, many are aggressive and can quickly overtake Carex lacustris and other native wetland plants.

Aphids

Aphids can infest Carex lacustris, causing distorted growth and reduced vigor. They suck sap from the plant, weakening it and potentially spreading diseases.

Slugs and snails

These pests can chew on the leaves of Carex lacustris, leaving holes and ragged edges, particularly in damp conditions.

Steps:

    • Dig up a clump of Carex lacustris in early spring or fall.
    • Divide the clump into smaller sections, ensuring each section has roots and shoots.
    • Replant the divisions in moist soil at the same depth as the original plant.
    • Water thoroughly and mulch around the base to retain moisture.

Compost

Improves soil structure and drainage for optimal growth.

Beneficial nematodes

Can help control soil-dwelling pests like slugs and some beetle larvae.