Giant Rhubarb

gunnera manicata

Also known as: ["Brazilian Giant Rhubarb","Dinner Plate Plant"]

Family: Gunneraceae Genus: Gunnera Category: Leaf Plants

Overview

A large, herbaceous perennial plant native to the Serra do Mar mountains of southeastern Brazil, known for its enormous, umbrella-like leaves.

Benefits & Perks

["aesthetic foliage","seasonal color change","wildlife attractant (bees, butterflies, birds)","shade tolerant"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Alismatales
Family: Gunneraceae
Genus: Gunnera
Botanical Name: Gunnera manicata

Plant Characteristics

Basic Information
  • Category: Leaf Plants
  • Suitable Location: shady garden bed near a water feature or pond
  • Suitable For:
    Collectors & Enthusiasts Outdoor Landscapers Wildlife Supporters
  • Is Weed: No
  • Allergenicity: low
Environmental Needs
  • Climate: {"temperatureRange":"5–25°C"}
  • Hardiness: {"zones":"7–10"}
  • Misting: rarely required, only if ambient humidity is very low
  • Drainage: Moderate to well-draining; avoid waterlogging.
  • Soil Type: Rich, loamy soil with high organic matter; well-draining but moisture-retentive.
Maintenance Level
  • Maintenance Level: high
  • Toughness Level: moderate
  • Pruning Frequency: As needed; annually for container-grown plants.
  • Pruning Intensity: Light to moderate; remove only dead or overgrown foliage.
Care Details

Ideal Sunlight Coverage:
Partial shade to full sun (4–6 hours of direct morning sun); protect from harsh afternoon sun.

Sunlight Tolerance Tips:
Acclimate gradually to direct sun; provide shade during peak hours; in containers, move to dappled light in summer.

Warning Signs: Yellowing leaves (overwatering); stunted growth (poor soil fertility); root rot (poor drainage).

Care Requirements

Care Difficulty
moderate

moderate

Sunlight

partial shade to full sun with protection from intense afternoon sun

Avoid direct midday sun; provide shade cloth if needed; rotate pot for even growth.

Watering

every 7–10 days during active growth, more frequently in hot weather

Water deeply to reach roots; ensure good drainage; avoid waterlogging during dormancy.

Soil

rich, moist, well-draining soil with plenty of organic matter

pH: Slightly acidic to neutral (pH 6.0–7.0).

Ensure good drainage; enrich with organic matter; maintain consistent moisture.

Temperature

Prefers cool to moderate temperatures (50–75°F/10–24°C); tolerates mild frost but thrives in cooler climates.

Protect from extreme heat; mulch in winter; avoid sudden temperature swings.

Fertilizing

every 4–6 weeks during spring and summer

Dilute fertilizer to half strength; apply to moist soil; avoid contact with leaves.

Propagation

Methods

Division of rhizomes; stem cuttings can also be used but are less common.

Step-by-Step Propagation Guide
  1. Divide rhizomes with sharp tools.
  2. Plant divisions at same depth.
  3. Water thoroughly.
  4. Maintain moisture.

Best Time: Early spring before new growth begins.

Environment

Warm, humid conditions with partial shade; protect from direct sun.

Medium

Rich, well-draining soil mix with compost and sand.

Hormone

Not typically required for division; rooting hormone can aid stem cuttings.

Timeline

Division: immediate establishment; stem cuttings: roots in 4–6 weeks, mature plant in 6–12 months.

Tools Needed

Sharp knife, gloves, pots, well-draining soil mix.

Quick Tips

Divide every 3–5 years to maintain vigor; ensure each division has roots and buds.

Pruning & Repotting

Pruning Guide
Method

Cut leaves at the base with clean tools; avoid cutting into healthy growth.

Pruning Plan

Remove dead or damaged leaves to maintain appearance and health; control size in containers.

Tools

Pruning shears, gloves, disinfectant.

Checklist

Disinfect tools; cut dead leaves; remove yellowing foliage; clean up debris.

Repotting Guide
Best Season

Early spring before active growth starts.

Pot Size

One size larger pot; ensure good drainage holes.

Method

Remove plant gently; trim roots if needed; place in new pot with fresh soil; water thoroughly.

Suggestions

Repot every 2–3 years or when roots fill container; essential for container-grown plants to prevent overcrowding.

Checklist

Choose appropriate pot size; prepare fresh soil mix; handle roots carefully; water after repotting.

Advanced Care Tips

Watering Mastery
Watering Checklist

Check soil moisture before watering; water deeply; ensure drainage; adjust for season.

How to Apply Water Properly

Water at the base, ensuring even moisture distribution; allow excess to drain; water early morning or late evening to minimize evaporation.

Pro Tip: Use a soaker hose to deliver water directly to the root zone.
Watering Schedule Tips

Keep soil consistently moist during active growth (spring/summer); reduce frequency in fall/winter to prevent root rot.

Soil Improvement

Add compost or well-rotted manure; incorporate sand for drainage; use mulch to retain moisture.

Temperature Stress Management
Signs of Temperature Issues

Leaf scorch in excessive heat; stunted growth or browning in cold stress.

Cold Stress

Slows growth; may cause leaf damage or dieback in prolonged cold; roots can rot in waterlogged soil.

Solution: Mulch heavily in winter; protect roots from frost; ensure good drainage to prevent waterlogging.

Hot Stress

Leaves wilt or scorch; growth slows; may drop older leaves to conserve energy.

Solution: Provide shade during peak heat; increase watering; use mulch to retain soil moisture.

Fertilizing Guide
Fertilizing Checklist

Use balanced fertilizer; dilute properly; apply during growing season; avoid overfertilization.

Fertilizing Method

Use balanced liquid fertilizer (10-10-10) every 4–6 weeks during growing season; reduce or stop in winter.

Common Problems & Solutions

Yellowing leaves in Gunnera manicata may indicate nutrient deficiencies, particularly nitrogen, or could be a sign of stress from overwatering, underwatering, or pest infestations.

Wilting in Gunnera manicata is often a symptom of water stress, either due to insufficient soil moisture or root damage from overwatering or root rot.

Leaf spots on Gunnera manicata may be caused by fungal or bacterial pathogens, leading to unsightly lesions, reduced photosynthetic efficiency, and potential leaf drop.

Rotting, particularly root or crown rot, can occur in Gunnera manicata when the plant is exposed to excessively wet conditions, leading to decay of plant tissues and potential plant death.

Toxicity Warning

Cats
Slightly Toxic

Cats are susceptible to mild toxicity from Gunnera manicata if they consume its roots or stems. The plant's toxic compounds can lead to gastrointestinal issues and skin irritation in felines.

⚠️ Symptoms:
vomiting diarrhea excessive grooming lethargy
🌿 Toxic Parts:
roots stems
⚡ Toxic If:

if eaten

Prevent cats from accessing the plant. If ingestion is suspected, seek veterinary advice immediately.
Dogs
Slightly Toxic

Dogs may experience mild toxicity if they ingest parts of Gunnera manicata, particularly the roots and stems. The plant contains compounds that can cause gastrointestinal upset and skin irritation in canines.

⚠️ Symptoms:
vomiting diarrhea drooling lethargy
🌿 Toxic Parts:
roots stems
⚡ Toxic If:

if eaten

Keep pets away from the plant, especially if they have a tendency to chew on vegetation. If ingestion occurs, consult a veterinarian promptly.
Humans
Slightly Toxic

Gunnera manicata contains toxic compounds, primarily in its roots and stems, which can cause irritation and discomfort upon ingestion. The plant's toxicity is not severe but can lead to gastrointestinal distress and skin irritation in sensitive individuals.

⚠️ Symptoms:
nausea vomiting diarrhea skin irritation
🌿 Toxic Parts:
roots stems
⚡ Toxic If:

if eaten

Handle with care, especially when preparing for consumption. Wash hands thoroughly after handling the plant, and avoid ingestion unless properly prepared or cooked.
Important: Keep this plant out of reach of children and pets. If ingestion occurs, contact poison control or veterinary services immediately.

Frequently Asked Questions

Q: How large can Gunnera manicata grow?

A: It can grow up to 6 feet tall and 10 feet wide, with leaves spanning up to 6 feet in diameter.

Q: Does Gunnera manicata require special care?

A: It needs rich, moist soil and protection from strong winds; in colder climates, the crown should be mulched with its own dead leaves for winter protection.

Q: Is Gunnera manicata toxic to pets?

A: The toxicity to pets is not well-documented, so it is advisable to keep pets away from the plant as a precaution.

Quick Reference
Family: Gunneraceae
Care: moderate
Light: partial shade to full sun with
Water: every 7–10 days during activ
Suitable For: ["collectors/enthusiasts","outdoor landscapers","wildlife supporters (attracts bees, butterflies, birds)"]
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