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Carex densa (Dense Sedge)
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© Jesse E. D. Miller, some rights reserved (CC-BY-NC) · iNaturalist

Carex densa

Dense Sedge

Western North America from British Columbia to Baja California

At a Glance

TypeGrass
FoliageDeciduous
Height12-30 inches (30-75 cm)
Width12-24 inches (30-60 cm)
Maturity3 years

Growing Zones

USDA Hardiness Zones

6 - 10
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancehardy

Key Features

Maintenancelow

Overview

Carex densa is a deciduous clumping perennial sedge reaching 12-30 inches (30-75 cm) tall and 12-24 inches (30-60 cm) wide, forming a tight bunch of upright to arching foliage. Leaves are flat, bright green to medium green, 0.1-0.2 inch (3-5 mm) wide and 8-20 inches (20-50 cm) long. Flowering stems are stiffly upright, triangular in cross-section, and bear a single dense head of 8-25 short spikes packed into a head 0.6-1.5 inches (1.5-4 cm) long; the head is brown to tawny at maturity. Bloom occurs from March through June depending on elevation. Plants form a discrete clump that expands by 1-2 inches (2.5-5 cm) per year without rhizomatous spread; mature clumps reach 18-24 inches (45-60 cm) wide within 4-5 years. Foliage yellows after bloom in dry summers but recovers with fall rain. Self-seeds modestly in open moist soil; volunteer seedlings can be transplanted or removed.

Native Range

Native to western North America from British Columbia through Washington, Oregon, and California to northern Baja California. Grows in seasonally wet sites: vernal pool margins, swales, low-gradient stream banks, and moist meadows at elevations from sea level to 4,000 feet (1,200 m). Persists on heavy clay soils that are flooded in winter and dry in summer.

Suggested Uses

Used in rain gardens, vernal pool plantings, native meadows, and streamside restorations, spaced 15-18 inches (38-45 cm) apart in moist sites. Plantings combine with Juncus patens, Sisyrinchium bellum, and Achillea millefolium in seasonally wet California meadows. Compatible with full sun in moist soils or part shade in drier conditions; tolerates clay and brief winter inundation.

How to Identify

Distinguished from other clumping Carex by a single dense head 0.6-1.5 inches (1.5-4 cm) long composed of many short, closely packed spikes. Differs from C. unilateralis by the absence of conspicuous bracts below the head and a more compact head outline. Pistillate scales are brown with green midribs; perigynia are 0.1 inch (3 mm) long with a short beak.

Appearance

Size & Dimensions

Height1' - 2'6"
Width/Spread1' - 2'

Reaches mature size in approximately 3 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks
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Blooms March through June, with peak inflorescence development in April at low elevations and May to early June in foothill populations. Each clump produces flowering culms over a 3-4 week window. Spikes hold their form for 6-8 weeks before perigynia disperse.

Detailed Descriptions

Flower Description

brown to tawny

Foliage Description

bright green to medium green

Growing Conditions

Sun Requirements

Requires 4-9 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)
357912
Soil Types
Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Water at planting and through the first growing season; established plants in seasonally wet sites tolerate summer drought once dormant. Foliage browns in dry summers and rebounds with fall and winter rain. Few pest or disease problems occur. Old foliage can be cut to 3 inches (7.5 cm) in late winter before new growth emerges; cutting reveals a clean clump for spring. Self-seeding is light to moderate in open soil and can be controlled by removing seedheads before perigynia ripen. Fertilization is not required.

Pruning

Foliage is cut to 3-4 inches (7.5-10 cm) above the crown in late February or early March before new growth begins. Spent flowering stems can be removed in early summer to limit self-seeding, or left to mature for habitat value. No mid-season grooming is required.

Pruning Schedule

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winterearly spring

Maintenance Level

low

Container Growing

✓ Suitable for container growing

Minimum container size: 3 gallons

⚠️ Toxicity Warning

Non-toxic