Dioon edule ‘Rio Verde’
 
Common Names Chestnut Dioon, Rio Verde Cycad
 
Zones 8B–11
 
Dioon edule ‘Rio Verde’ is a cold-tolerant cycad native to the Sierra Madre Oriental near Rio Verde, San Luis Potosí, Mexico. This regional form is prized for its compact trunk, silvery-blue juvenile foliage, and adaptability to dry, rocky soils. It thrives in oak woodlands and thorn forests at elevation, making it ideal for xeric landscapes and frost-prone gardens.
 
Key Features
Growth Habit: Upright, symmetrical; slow-growing
Height: Typically 3–6 ft; trunk may reach 1–2 ft over decades
Trunk: Rough, scaly; retains persistent leaf bases
Leaves: Pinnate; 3–4 ft long; leaflets lanceolate, flat to slightly V-shaped; color ranges from light green to silvery-blue depending on sun exposure
Petiole: Short; spiny near base
Inflorescence: Dioecious; male cones cylindrical and tan; female cones woolly and compact
Fruit: Seeds large, tan to brown; toxic if ingested
Ecology: Native to deciduous thorn forests and oak woodlands at elevations over 1000 ft; drought and frost adapted
 
Growing Conditions
Light: Full sun to partial shade; brighter exposure enhances blue tones
Watering: Moderate; water regularly but allow soil to dry between cycles
Soil: Well-draining mix; tolerates mildly acidic to mildly alkaline pH (6.1–7.8)
Temperature: 45–95°F (7–35°C); tolerates brief dips to 15°F2
Humidity: Moderate; adaptable to dry air
Propagation: By seed; slow germination and juvenile development
Tolerance: Drought, frost, and rocky soils; avoid waterlogging
 
Landscape Use Ideal for xeriscapes, porch containers, and frost-prone gardens. Pairs well with Agave parryi, Nolina texana, and Quercus polymorpha for a rugged, highland palette.