Ceratozamia robusta is the largest of the Ceratozamia genus. C. robusta originates from Mexico, Belize, and Gueatamala. Height of stems can be up to 6 feet. Several of my largest specimens are over 13" in diameter. Stems can be solitary or branching at the base. Leaves grow very upright to sometimes arching, with a height of 12 feet. The petiole of the leaf is heavily armed with spines. Leaves emerge either a light green or bronze color. C. robusta is a fast growing cycad. I have had several flushes of growth in one year. It prefers filtered light, but will tolerate full sun. In full sun the leaves may turn yellow. I find this plant best used in shady areas of the landscape. Since it grows large in size, use it as a focal-point specimen or as a background plant. C. robusta will tolerate light frosts with no damage.
Large specimen in 15 gallon pot.
Green emergent leaf.
Immature female cone. This cone was aprox. 12" in size.
Below left is a photo of this cone after harvesting seed.
This plant has green emergent foliage
Male Cone
This plant has green emergent foliage
Female cone with mature seeds.
Note spines on petiole.
Close-up of female cone (left) aprox. 8" long.
Bronze emergent leaf form.
Examples of new leaves. Bronze emergent form.
C. robusta female female cone with ripe seeds.
Typical C. robusta seeds.
Cones
Ceratozamia robusta produces large cones. Female cones can be larger than 13". Male cones can also exceed 12" in length. After being pollinated it can take several months to a year for seeds to become ripe. The cone will start to fall apart when seeds are ready to harvest. The fruit coating or sarcotestra is white at first, but quickly turns brown when exposed to open air. Seeds are about 1" in length. "Ripe" seeds generally need another 3-6 months before the embryos are fully developed and ready for planting.
