Giant Dioon

Dioon spinulosum

• Common name: Giant dioon, gum palm
• Scientific name: Dioon spinulosum
• Family name: Zamiaceae
• Origin: Mexico
• Height: 5-12 ft in gardens – in the wild, it has been known to grow up to 50 ft tall over centuries
• Width: 6-12 ft
• Growth: Slow
• Zone: 9b-11
• Light needs: Full sun – partial sun
• Salt tolerance: Moderate
• Soil/pH/Texture: Prefers well-drained, moist soil. It an grow in many soil types, including soils low in nutrients/rich in limestone, and rocky soils. Prefers neutral to alkaline soil (pH 7.0-7.5)
• Moisture: Regular water needs – water only to keep soil moist, not boggy.
• Drought tolerance: Moderate
• Pests/Diseases: No pests and diseases are of particular concern.
• Growing conditions: Best grown in well-drained, moist, alkaline soil, in full sun or partial sun. Not picky about soil types – can be grown in all sorts of well-drained soil textures, including low-nutrient soils. This plant is a fast grower for cycads, but still slow-growing compared to most plants – growth is slightly faster if planted in a sunny area.
• Characteristics: This cycad has a thick, ridged trunk which may be over 12 inches in diameter. Leaves grow out radially from the top of the trunk. Leaves are compound pinnate and grow 5-7 ft long, with 120-240 leaflets on each leaf. Leaflets are flat with small thorns along the margins, and taper to a sharp point. Male and female cones are borne on different plants, and must be pollinated by hand. Seeds are round and light brown.
• Propagation: By seed or by offsets
• Facts: This plant is endangered in the wild due to habitat destruction and over-collection. It is one of the tallest cycads in the world. Cycads are an ancient lineage of plants, emerging in the Mesozoic era (time of the dinosaurs).
• Designer considerations: Great as a specimen planting due to its dense, distinct foliage and exotic look. It can also be an indoor plant or greenhouse plant. It tolerates partial shade, so it is a good choice for understory planting.