Native to the Japanese island of Kyushu, this slow-growing, long-lived plant is a cycad (contrary to its common names) that may have symbiotic relationships with Nitrogen-fixing cyanobacteria (known as blue-green algae). This cycad is extraordinarily beautiful, and its presence feels majestic.
Cycas revoluta (King Sago Palm, Japanese Funeral Palm) [sometimes sold as Cycas nana]
Hardiness Zones: 9-10
Height: to 3 meters (10 feet) tall
Diameter: to 3 meters (10 feet) across
Growth Rate: very slow
Age: These may not grow to be 10 feet tall for 50 years.
Root System: King Sago Palms begin teir lives with a primary taproot, although lateral roots become more efficient (relatively) with age. These also develop coralloid roots that work with Nitrogen-fixing cyanobacteria. Once mature, these also produce adventitious roots for pups/suckers/offsets.
Subspecies: subsp. brevifrons, planifolia, prolifera, robusta
Tolerates: drought (moderate once established), cold temperatures (to -10 degrees Celsius or +10 degrees Fahrenheit) for brief times once established (will suffer frost damage, though)
Problems (major): mealybugs (if not detected early), cycad aulacaspis scale
Problems (minor): spider mites (under dry conditions)
Poisonous: neurotoxin present throughout plant, poor preparation before ingestion may cause paralysis, irreversible mental ailments, or death
Soil requirements: prefers light/sandy, humus-rich/humusy, slightly acidic soils; appreciates slow-release fertilizers and mulch; excellent drainage required; intolerant of alkaline soils
Air requirements: prefers medium to high humid
Watering requirement: moderate, keep soil moderately moist with brief dry periods between watering
Sun requirement: full sun or partial shade (preferred)
Leaves: occur in frond-like, shiny, deep-green, arching segments with a prominent midrib, forming symmetrically around the base, to 1.5 meters (5 feet) in length and 24 centimeters (9 inches) in width
Leaflets: to 18 centimeters (7 inches) long, with sharp, terminal tips (far lesser sharp than some cycads (such as Encephalartos horridus)
Cones (male): erect, elliptical, yellow, to 45 centimeters (18 inches) tall
Cones (female): globular, yellow, produce orange seeds to 4 centimeters (1.5 inches) across
Monoecious or Dioecious: dioecious
Seeds require stratification: exposure to darker, cooler conditions improve germination
Cycads, including Cycas revoluta, appear to have a symbiotic relationship with Nitrogen-fixing cyanobacteria through specialized roots growing upwards (coralloid). This cycad produces offsets/suckers around its base with age. Seeds should be placed in a somewhat cool place for 8-12 weeks before planted. Old, dry seeds should be soaked for roughly 24 hours before placed in soil to germinate. Germination, once in the soil, will occur within 12 weeks.
These are frequently used as shrubs, bonsai, or other ornamental garden plants in applicable, tropical regions. Some Pacific Island natives have used this for food in the past, although EXTREME caution must be used, as poor preparation may cause death upon ingestion. Do NOT consume.
All of the images provided were taken by me. They may be used for educational/informational purposes only, provided that this article/online journal is appropriately cited first.