What hardiness zones is Gunnera manicata suitable for?

Gunnera manicata is suitable for USDA hardiness zones 7, 8, 9, 10.

What are the sun requirements for Gunnera manicata?

Gunnera manicata requires Part Sun.

How much water does Gunnera manicata need?

Gunnera manicata has High water needs.

1 / 2

Perennials

Gunnera manicata

gunnera

GunneraceaeSouth America

At a Glance

TypePerennial

HabitClumping

FoliageDeciduous

Height6–9 feet (180–270 cm)

Width10–16 feet (300–490 cm)

Maturity5 years

Growing Zones

USDA Hardiness Zones

7 - 10

Zone 7

Zone 8

Zone 9

Zone 10

These zones indicate the coldest temperatures this plant can typically survive.

Frost Tolerancehardy

Key Features

Deer Resistant

Maintenancemoderate

Overview

Gunnera manicata, commonly called Brazilian giant rhubarb or giant gunnera, is an enormous clump-forming herbaceous perennial in the family Gunneraceae, native to the coastal mountain forests of southern Brazil, particularly the Serra do Mar range. It is among the largest-leaved herbaceous plants in cultivation, with individual leaf blades commonly exceeding 5 feet (150 cm) across, supported by massively thick, spiny petioles up to 8 feet (2.4 m) long covered in stout prickles. Plants reach 6–9 feet (180–270 cm) tall and spread 10–16 feet (3–5 m) in maturity, forming an impenetrable cathedral of foliage. In early summer, thick, conical, reddish-brown flower spikes 3–4 feet (90–120 cm) tall rise at ground level between the petioles, bearing thousands of tiny flowers followed by small orange-red berries. Gunnera manicata harbors endosymbiotic Nostoc cyanobacteria in specialized glands at stem bases, which fix atmospheric nitrogen for the plant — a unique adaptation among angiosperms. The plant is fully deciduous in all but the mildest climates, dying back to a massive crown in autumn. It requires a large, moist, sheltered site and is one of the most dramatic specimen plants achievable in Pacific Northwest gardens.

Native Range

Native to the coastal mountains of southern Brazil, primarily the Serra do Mar in the states of Santa Catarina and Rio Grande do Sul, where it grows in humid forest margins, streambanks, and clearings at moderate elevations. The species is adapted to high rainfall, consistently moist soils, and cool to mild summers — conditions closely matched by Pacific Northwest coastal gardens.

Suggested Uses

Gunnera manicata is the supreme choice for a bold, architectural specimen at a pond, stream, or bog garden edge in Pacific Northwest gardens with adequate space and moisture. The prehistoric scale of the plant is unmatched among hardy perennials and creates a dramatic focal point visible from a distance. A single well-established specimen dominates a large area of garden. Pairs effectively with Rodgersia, Ligularia, Lysichiton americanus, and giant ornamental grasses at water features. Not appropriate for small gardens. An outstanding plant for educational gardens demonstrating plant diversity and extreme growth forms.

How to Identify

Gunnera manicata is unmistakable by scale alone: the enormous kidney-shaped to rounded leaf blades, 3–6 feet (90–180 cm) across, with prominent, raised veins and coarsely toothed margins, are without rival among hardy herbaceous perennials. The stout petioles, 4–8 feet (120–240 cm) long, are covered in stiff, sharp, reddish spines. Conical reddish-brown flower spikes 3–4 feet (90–120 cm) tall are produced at ground level among the petioles in early summer. No other cold-hardy perennial approaches this plant's leaf size.

Appearance

Size & Dimensions

Height6' - 9'

Width/Spread10' - 16'

Reaches mature size in approximately 5 years

Colors

Flower Colors

red

brown

Foliage Colors

green

Fall Foliage Colors

yellow

brown

Bloom Information

Bloom Period

~6 weeks

Summer

Gunnera manicata produces its flower spikes in early to midsummer, typically June through July in Pacific Northwest gardens, emerging from the base of the plant among the petioles before or alongside the developing leaves. The cone-shaped flower spikes are reddish-brown, 3–4 feet (90–120 cm) tall, and botanically interesting rather than showy; they are followed by small orange-red berry-like fruits. The primary ornamental feature is the extraordinary foliage, which reaches maximum size in mid to late summer before frost kills the leaves in autumn.

Detailed Descriptions

Flower Description

Reddish-brown (flower spike)

Foliage Description

Dark green, enormous, prominently veined, coarsely toothed

Growing Conditions

Sun Requirements

Full Sun

Partial Shade

Requires 4-8 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 - 7.0(Neutral)

357912

Soil Types

loamclaypeat

Drainage

moist

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

3–5 years

Care & Maintenance

Care Guide

Plant gunnera in consistently moist to wet, deep, humus-rich soil in full sun to light partial shade, with shelter from strong wind. The species demands reliably high moisture year-round — a streambank, bog garden margin, pond edge, or permanently moist border is ideal. The crown and root system require adequate space: allow at least 10–16 feet (3–5 m) in all directions. In Pacific Northwest gardens, provide winter crown protection by folding the dead leaves over the crown after the first hard frost to insulate the growing points, then remove them in early spring. Apply a generous compost mulch in autumn. Fertilize with a balanced fertilizer in spring as growth resumes to support the enormous leaf production.

Pruning

After the first hard autumn frost kills the leaves, cut the dead petioles back partially and fold or pile them over the crown to form an insulating mound — this is the critical winter protection method for the crown in colder parts of the Pacific Northwest (USDA zones 7 and colder). Remove the protective mulch and dead material in early spring before new growth emerges. In early spring, cut all remaining dead material to the ground. No summer pruning is required. Remove the flower spikes at the base if self-seeding is not desired.

Pruning Schedule

fallearly spring

Maintenance Level

moderate

⚠️ Toxicity Warning

Non-toxic