Johnson's Grass Tree (Xanthorrhoea johnsonii)

Johnson's Grass Tree

Xanthorrhoea johnsonii

It stands like a prehistoric sentinel, with spiky leaves and a tall flowering spike. Evergreen perennial succulent tree; common name: Johnson's Grass Tree.

Full sun
0.5/week
Moderate
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Plant Needs

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Sunlight Full sun exposure for optimal flowering; tolerates partial shade but may produce fewer blooms
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Watering Drought-tolerant; water deeply only when the top 20–30 cm of soil is completely dry to avoid root rot
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Temperature Hardy to light frost; avoid prolonged temperatures below 5°C; thrives in warm temperate to subtropical climates
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Characteristics

  • Leaf: Long, narrow, rigid, grey-green leaves forming a dense rosette atop the trunk
  • Flower: Tall, cylindrical spike (up to 3 m) with small, creamy-white, fragrant flowers
  • Stem/Trunk: Thick, woody trunk covered in accumulated dead leaf sheaths
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Care Guide

Watering

Water deeply once every 2–3 weeks during active growth periods

Fertilization

Apply diluted, low-nitrogen, slow-release feed once annually if soil is nutrient-poor. Over-fertilization can stunt growth and damage the slow-developing root system

Composted eggshell powder:Sprinkle a thin layer of crushed, composted eggshells around the base of the plant once yearly; avoid direct contact with foliage
Pruning
  • Remove dead, brown leaves from the rosette base to maintain appearance and improve airflow
  • Trim spent flower spikes after blooming to redirect energy to foliage and trunk growth
  • Avoid cutting into the woody trunk, as it has limited regenerative capacity
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: ASPCA: No recorded toxicity to cats

Humans: No known toxic effects to humans

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Garden Uses & Culture

Culture: N/A

Usage: Ornamental garden plant; traditional Indigenous Australian medicinal uses for resin and leaves