Family: Cycadaceae
Native to southern Japan, the king sago palm can tolerate temperatures down to the high teens. This slow-growing palm produces shiny, arching, palm-like leaves set atop a stout trunk. Mature palms can take 50 years to reach ten feet tall while producing leaves only once a year. Immature palms can flush new sets of leaves multiple times a year. The plant is dioecious; viable seeds will form only when both male and female trees are in range of each other. Males produce upright yellowish ellipsoid pollen cones, and females produce seeds encased in a golden cone. This palm is an excellent choice for an indoor plant as it grows well in the shade.
Plant Uses:
- Container plant
- Hedge
- Indoor plant
- Ornamental
- Specimen
Plant Dangers:
- Allergenic
- Toxic to animals
High Risk Traits:
- Toxic to animals and humans (all parts poisonous)
- Host to fungi and scale pests (45+ fungi; cycad scale)
- Bird- and mammal-dispersed seeds (attractive, showy, survive gut passage)
- Widely cultivated and intentionally introduced worldwide
- Nitrogen-fixing (via cyanobacteria in coralloid roots)
- Tolerates shade and wide soil conditions
- Produces viable seed (up to 1,000 seeds per large plant)
Low Risk Traits:
- No evidence of naturalization or weediness anywhere
- No spines, thorns, burrs, or allelopathic effects
- No vegetative fragmentation in wild
- Dioecious (obligate outcrosser), no self-compatibility
- Very slow to mature (15+ years to reproduce)
- Large seeds; no wind or adhesive dispersal; no contaminant risk
- No seed dormancy (no persistent seed bank)
- Not a fire hazard; limited regeneration after mutilation
- No congeneric weeds reported
