|Germination time:||Up to a year|
|Adult size:||Up to 6 or 7 m (20 ft)|
|Lighting:||Full to medium|
|Watering:||Let soil dry a bit|
|Fertilization:||Monthly during active growth|
|Air moisture:||Tolerates dry air, but prefer moist air|
Cycas revoluta (common names: King Sago palm or Sago palm) is a species of cycad, native to Southeastern Japan.
Cycas revoluta, just like every other cycad, is not a palm but well a gymnosperm, thus relating it with conifers; the palmed shape of its leaves denotes convergent evolution of the palms, a true Angiosperm family.
Cycas has palm-like pinnate leaves, arranged spirally. Folioles are very similar to conifer needles and are thick and rigid. The trunk (caudex) is cylindrical and somewhat looks like (for younger specimens) a small pineapple as for its shape and "needles", that are actually persistent small (one, sometimes two centimeters long) brown petiole bases.
Cycas rarely blossom in indoor conditions. When they do in nature, it and the other member of its family (Cycadaceae) have a distinct way of doing it than other cycads. While male plants will grow a single large pollen cone, the female ones will, instead of growing a cone like the others, grow leaf-like structures that will contain the seeds in the lower margin.
Cycas revoluta, just like the other cycads, are very slow growers; if mature plants produce one full crown of new leaves annually, younger ones will only produce one or two new ones every year.
All cycads are easy of care and popular among collectors. Their very slow growth is however a little prohibitive for those looking for an immediate impact in the house or the greenhouse - it is better in that case buy an older and bigger subject that already reached the desired size. If given many decades, though, they will become massive plants, with a trunk that can potentially reach up to 2 or 3 meters.
Cycads will tolerate anything between intense to medium lighting; they will, however, prefer intense light in indoor conditions.
Cycads are usually obtained by planting seeds; however, seeds take up to a year to germinate, and the plant keeps growing very slowly for its whole life. Offshoots sometimes occur on the trunk of mature plants; these can be stroked to produce a new plant.
Pests and diseases
Those very hardy plants are rarely targeted by pests and diseases. However, the Asian Cycad scale (Aulacaspis yasumatsui) is a disease that does attack cycads. It originates from Thailand and has been spread to Hawaii, the West Indies and the South of the United States. It looks like a white powder on the leaves and is devastating to cycad cultures. This disease, however, is the result of the importation of sick plants, and therefore, growers who grow their cycads from seeds without ever importing plants from abroad will sell sane plants that will not develop it.
Cycads can be re-potted at all time during the year; they however enjoy being root-bound, so they don't need frequent re-potting. Mulching is appreciated by those plants.
This plant is very toxic, to humans and animals alike. Pets are particularly prone to fall ill from ingestion of its leaves, since they tend to find it palatable. All parts of the plant are toxic; however, the seeds contain the highest level of the toxin cycasin. Cycasin causes gastrointestinal irritation, and in high enough doses, leads to liver failure. Other toxins include Beta-methylamino L-alanine, a neurotoxic amino acid, and an unidentified toxin which has been observed to cause hindlimb paralysis in cattle. The plant may leave permanent internal damages or even kill several hours following ingestions (symptoms begin to appear some 12 hours after consumption) and a poison control center or a doctor must immediately be called to seek medical advice.