Cycas revoluta

1. Brief Description

Cycas revoluta, commonly known as sago palm or Japanese sago palm, is a slow-growing cycad with glossy, dark green leaves and a palm-like appearance, though it is not a true palm. Its architectural form and dramatic foliage make it a standout choice in landscape design.

With its striking fronds and cylindrical trunk, it is often used as a specimen plant, particularly in tropical or subtropical themed gardens.

2. Botanical Information

• Taxonomy: Family Cycadaceae; Genus Cycas; Species revoluta Thunb.

• Common names: Sago palm, Japanese sago cycad, King sago

• Native range: Southern Japan, especially the Ryukyu Islands, and coastal regions of East Asia

• Morphology:

  • Trunk: Slow-growing; young plants have subterranean or short surface trunks, adults can develop cylindrical trunks up to 6 m in natural habitats

  • Leaves: 0.5–1.5 m long, pinnate, arranged in rosettes; leaflets are stiff with revolute (curved) margins

• Reproduction: Dioecious (male and female plants separate). Males produce cones; females develop large leaf-like megasporophylls

• Additional Notes: Symbiotic blue-green algae (Anabaena) capable of nitrogen fixation may be present beneath leaves and at the root crown

3. Growing Conditions

• Light: Tolerates full sun to partial shade; dense shade may reduce frond density

• Soil: Prefers well-drained, sandy-loam to medium-textured soils; waterlogged or heavy clay soils can compromise root health

• Water: Established plants tolerate some drought; young plants require regular watering, but avoid prolonged waterlogging

• Climate & Frost: Thrives in mild subtropical climates; sensitive to frost; some sources indicate tolerance down to approximately −9 °C

• pH & Drainage: Adapts to neutral to slightly alkaline soils; excellent drainage is critical

4. Care Guidelines

• Pruning / Form Maintenance: Generally does not require pruning; remove dead fronds and old petioles to maintain appearance

• Drainage & Root Health: Poorly drained soils can lead to root rot; drainage must be carefully monitored, especially for indoor or greenhouse cultivation

• Watering Program: Regular watering for newly planted specimens; once established, reduce frequency but do not allow complete drying

• Protection & Propagation: Winter protection may be required in cold climates; propagation by seeds or basal offsets is possible, though growth is very slow

• Toxicity Warning: All parts of the plant, especially seeds and fruits, are toxic and may pose a risk to pets and children

5. Landscape Use

• Specimen Plant: Its architectural form and tropical appearance make it an excellent focal point in gardens

• Small-Scale Tropical Theme Gardens: Effective in tropical or subtropical landscapes due to frond shape and overall form

• Borders / Pathways: Can be positioned along walkways, entrances, or boundaries with width and height carefully managed

• Container / Terrace Use: Suitable for large containers on terraces or verandas due to slow growth, though it will not attain the same freedom as in-ground planting

• Drought-Tolerant / Low-Maintenance Areas: Can be used in xeriscape or drought-adapted landscapes if provided with adequate light and drainage; cold protection may be necessary