Dioon spinulosum

giant dioon
This cycad makes a statement indoors or in mild-climate gardens. Beautiful in pots. Needs good drainage, regular water in warm seasons. Grows large over decades in the garden.
height 4–20ft
width 4–10ft
tolerates Drought, Heat, Pots
water
needs		 Low – Moderate
water
info		 Cycads need good drainage to thrive, and this one requires average water once established. Water it deeply when the plant is mostly dried out, but not completely dry.
hardy
to		 25F
exposure Full Shade – Full Sun
indoor
outdoor		 In or Out
drainage In Ground: Cactus Mix, In Pots: Cactus Mix, Tolerates Sandy Soil
fertilizing All Purpose
origin Mexico
california
native		 No
sunset
zones		 13, 19–24, H2

Sunset Zones Map

Growing Notes

Indoors be sure this plant does best if it gets some sun during the day, but can also grow in bright indirect light. Be sure to keep it back from high traffic areas as damaged leaves do not recover.
Cycads look adorable when they’re small! And it’s a good thing, too, because these plants are slow-growing (though this one is fast... for a cycad), taking decades to become large specimens, and much longer to achieve the scale of plants in habitat. Cycads flush leaves infrequently, often only once a year, but when they do it’s quite the show, as they flush a whole crown of leaves all at once.
Since cycad leaves are slow to replace themselves, be extra careful not to physically damage them.
As older leaves turn brown, they can be pruned back to the trunk and removed.
Be sure to fertilize your cycad in the spring through summer. Without a good amount of food, your cycad might skip a year of flushing its leaves!

Special Interest

Cycads look like palm trees, but they are gymnosperms that bear either male or female cones, making them more closely related to a pine tree than a palm tree. Their similar appearance is created by convergent evolution, whereby dissimilar plants adapt similar forms to survive.

Since they require a male and female plant to produce and are very slow growing, large cycads are usually quite expensive and rare.

The oldest potted plant on earth is a cycad: Encephalartos altensteinii in the Kew Gardens collection. This plant was brought to England and planted there in 1775, when it was already likely quite old.

A Cycas rumphii was planted in the Lincoln Park Conservatory in Chicago to mark its completion in 1890. It was estimated at over a hundred years old when planted, and it still grows in the collection today. It is older than Chicago itself, which was incorporated in 1833.