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Schoenoplectus tabernaemontani (Soft-stem Bullrush)
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© JaneR, some rights reserved (CC-BY) · GBIF

Schoenoplectus tabernaemontani

Soft-stem Bullrush

At a Glance

HabitUpright
FoliageDeciduous
Height4-9 feet (1.2-2.7 m)
Width6-12 feet (1.8-3.5 m)
Maturity5 years

Growing Zones

USDA Hardiness Zones

4 - 9
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancehardy

Key Features

Deer ResistantContainer Friendly
Native to North America
Maintenancelow

Overview

Schoenoplectus tabernaemontani is a herbaceous wetland sedge reaching 4-9 feet (1.2-2.7 m) tall, growing in dense colonies from spreading rhizomes to form patches 6-12 feet (1.8-3.5 m) across after 3-5 years. Stems are smooth, round in cross-section, soft when squeezed, blue-green to grey-green, and 0.3-0.6 inches (8-15 mm) thick. Leaves are reduced to bladeless sheaths at the stem base; the green stems carry out photosynthesis. Inflorescences emerge near the stem tip as drooping clusters of red-brown to grey-brown spikelets 0.2-0.4 inches (5-10 mm) long from June through September. Achenes mature in late summer and disperse by water and waterfowl. Plants spread through rhizomes, with new shoots emerging from the rhizome tip 4-12 inches (10-30 cm) ahead of the parent clump each year. Stems die back to the rhizome after first hard frost; new growth emerges from underwater rhizomes in spring as water temperatures rise above 50 F (10 C). The species occurs as a primary emergent vegetation component of freshwater marshes, lake margins, and slow stream banks across temperate North America. Aggressive rhizome spread makes containment necessary in landscape ponds; plants overgrow water-lily mats within 2-3 seasons.

Native Range

Native across North America from Alaska and southern Canada to Mexico, and across Eurasia from Western Europe to Japan. Grows in shallow standing water 4-30 inches (10-75 cm) deep in freshwater marshes, pond margins, lake shores, and slow-moving streams at 0-7,500 feet (0-2,300 m) elevation.

Suggested Uses

Used in pond margins, rain gardens, constructed wetlands, and water purification systems in zones 4-9. Spaced 18-24 inches (45-60 cm) apart in mass plantings for habitat or filtration; closer spacing accelerates rhizome interlocking. Aggressive spread makes the species unsuitable for small water gardens or bog gardens under 100 sq ft (9 sq m) without containment.

How to Identify

Identified by tall round soft stems 4-9 feet (1.2-2.7 m) tall and 0.3-0.6 inches (8-15 mm) thick, lacking distinct leaves above the basal sheaths, with a drooping cluster of red-brown spikelets near the stem tip. Distinguished from S. acutus (hard-stem bullrush) by softer compressible stems and lighter blue-green color. Distinguished from Typha cattails by round stems and small spikelets (rather than dense brown cylindrical seedheads at the stem tip).

Appearance

Size & Dimensions

Height4' - 9'
Width/Spread6' - 12'

Reaches mature size in approximately 5 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~12 weeks
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June through September across most of the range, with peak flowering in July and August. Individual spikelets release pollen for 4-7 days; the species is wind-pollinated. Total bloom period at the colony level lasts 8-12 weeks. Achenes mature 4-6 weeks after pollen release and persist on dried inflorescences through winter.

Detailed Descriptions

Flower Description

Red-brown to grey-brown

Foliage Description

Blue-green to grey-green

Growing Conditions

Sun Requirements

Requires 6-12 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 Range6.0 - 8.0(Neutral)
357912
Soil Types
Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

3-5 years to fill 6-12 ft (1.8-3.5 m) patch

Care & Maintenance

Care Guide

Plant rhizome divisions in 4-30 inches (10-75 cm) of standing water in spring after water temperatures reach 50 F (10 C); plants tolerate brief drying but die in extended drawdown without damp soil. Plant baskets or root barriers in landscape ponds limit rhizome spread; uncontained colonies expand to fill the pond within 3-5 years. Salt tolerance is moderate, with plants persisting at salinities up to 5 parts per thousand but declining above 10 parts per thousand. Plants tolerate seasonal flooding to 4 feet (120 cm) and brief ice cover. Few diseases trouble the species; aphids occasionally colonize developing inflorescences without long-term harm. Cut dead stems in late winter before new shoots emerge; previous-year stems left in place can pierce emerging spring shoots and reduce stand density.

Pruning

Cut spent stems back to the water line in late winter or early spring before new shoots emerge in May. Inflorescences and stems can be cut for fresh or dried floral use anytime from July through October. Escape rhizomes are removed by hand or with a sharpened spade at least once per season to limit colony spread.

Pruning Schedule

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winterearly spring

Maintenance Level

low

Container Growing

✓ Suitable for container growing

Minimum container size: 7 gallons

⚠️ Toxicity Warning

Non-toxic