Does it need full sun?

It prefers partial shade to protect the leaves from scorching.

How much water does it need?

It needs consistently moist to wet soil, ideally near a water feature.

Plant guide

Giant rhubarb.

Gunnera manicata

Pronounced GUN-er-uh man-ih-KAY-tuh

Also known as Brazilian Giant Rhubarb, Brazilian Giant-rhubarb

The giant rhubarb is a massive, prehistoric looking plant that loves damp, boggy spots in the garden. It produces enormous, umbrella like leaves that can reach several feet across. You will need plenty of space to let this beauty truly show off.

Another photo of Giant rhubarb — Photo by Josiah Londerée (CC BY) via iNaturalist

At a glance

Care level: Moderate
Plant type: Perennial
Light: Partial shade to full sun
Indoor light: Bright indirect
Water: Every 1 to 3 days
Mature size: 8 to 10 feet tall
Growth rate: Fast
Hardiness: USDA 7 to 10
Bloom time: Mid to late summer

Care

Keep the soil consistently wet, as this plant hates drying out. Watch for wilting leaves during hot spells, which signals it needs more water. In colder climates, protect the crown with mulch during the winter months.

Watering: Keep the soil constantly moist or even waterlogged.
Feeding: Feed with a balanced liquid fertilizer during the active growing season.
Pruning: Remove dead or damaged foliage in late autumn after the first frost.
Repotting: Repot only if the plant has outgrown its container, though it prefers being planted directly in the ground.
Soil: Rich, moisture retentive soil
Soil pH: 6.0 to 7.0
Temperature: -10 to 30°C
Humidity: 60 to 90%
Drought tolerance: Low
Lifespan: Perennial, typically 10 to 20 years.
Deer and rabbits: High

Signs it needs repotting

Roots growing out of the drainage holes.
Stunted growth despite regular watering.
Soil drying out too quickly.

Safety

People: The plant is not toxic, but the stiff hairs on the stems and leaves can cause significant skin irritation.
Pets: This plant is not known to be toxic to cats or dogs.
Children: The large, prickly stalks pose a risk of scratches and should be kept away from small children.
Contact allergens: The stiff, prickly hairs on the stalks can cause mechanical skin irritation and dermatitis.
Airborne allergens: There are no notable airborne allergen risks associated with this plant.
Edibility: The plant is not considered edible and should be avoided.

How to identify it

Massive, umbrella shaped leaves
Spiky, rough leaf stalks
Large, cone shaped flower spikes
Thrives in boggy soil

Height: 2 to 3m
Spread: 3 to 4m
Leaves: dark green, deciduous
Flowers: green, red, 1 to 2cm
Fruit: orange, red, Autumn

Problems to watch for

By symptom

Plant problems by symptom

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Growing it

Propagation: division, seed
When to plant: Spring
Overwintering: Cut back the leaves after the first frost and cover the crown with the dead foliage to protect it from freezing temperatures.
In containers: It is generally too large for containers unless you have a massive, specialized tub.

Division

1. Wait for early spring before new growth starts.
2. Carefully dig up the large rhizome.
3. Use a sharp spade to divide the clump into smaller sections.
4. Replant immediately in moist soil.

Plant near a pond or stream to ensure the roots stay constantly hydrated.

Grows well with

Hostas · They share similar shade and moisture requirements.
Ligularia · Their dark foliage and yellow flowers contrast beautifully with the giant leaves.
Ferns · They provide a delicate textural contrast to the massive leaves.

Similar species

Gunnera tinctoria · It is a smaller relative that is often confused with this species.

Science

Family: Gunneraceae
Genus: Gunnera
Order: Gunnerales
Class: Magnoliopsida
Native range: South America, specifically Brazil.
Conservation: It is not currently listed as endangered, though it is invasive in some parts of New Zealand and Ireland.

It thrives in high humidity and boggy soils, often found near streams in its native range.

Value to wildlife: provides dense cover for small animals
Pollinators: bees, beetles
Uses: ornamental pond edge, architectural focal point

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 1/9
Soil reaction: 5/9
Light: 4/9
Temperature: 6/9
Moisture: 9/9
Nutrients: 7/9

Taxonomy resolved against GBIF.

Questions people ask

Does it need full sun?: It prefers partial shade to protect the leaves from scorching.
How much water does it need?: It needs consistently moist to wet soil, ideally near a water feature.

Where the name comes from

It is named after the Norwegian botanist Johan Ernst Gunnerus, while the species name manicata refers to the sleeve-like hairs on the stems.

Good to know

It is often called the giant rhubarb due to its appearance.
The plant requires massive amounts of water to maintain its size.
It is native to the cloud forests of Brazil.

Also in

Deer-resistant plants

Keep your giant rhubarb growing

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.