Dioon sonorense

Cultivation Details

Dioon sonorense is native to the arid and semi-arid regions of northwest Mexico, growing in a region where the mean annual rainfall is around 250 - 500mm, falling mainly in the summer^[1]. In cultivation it is known to withstand several degrees of frost without damage^[1]. Most species of Dioon are easily cultivated and grow with minimal care^[1]. The stems of Dioon species are clothed in a thick armour of old leaf bases that protect them from the frequent fires that pass through their habitat. Their trunks are also clothed in a thick layer of dense, wooly hairs which persist and give protection until burned off^[1]. Species in this genus form structures known as coralloid roots. These roots branch off from the taproot or secondary roots and are distinctive in that they grow laterally or upward, forming a nodular mass at the apex. These coralloid roots occur slightly below or slightly above the soil surface and generally contain cyanobacteria, also known as blue-green algae. These are able to fix atmospheric nitrogen and make it available as a nutrient to the plant. The ability to extract this important nutrient from the air explains how many cycad species are able to survive on almost sterile soils^[1]. A dioecious species, with individual plants producing either all male or all female cones. Therefore both male and female forms of the plant need to be grown if seed is required^[1]. Female plants only produce one seed cone at each reproductive cycle, which generally occurs once every three to four years. This cone can take more than one year to mature^[1]. The ovoid cones of this species are 35 - 50cm long and 20 - 27cm in diameter, covered with a dense layer of short woolly hairs. They can weigh up to 18 kilos^[1].