Mostly occurs as dioecious shrub, often at high altitudes, rarely seen as a tree to 20m tall. Branches spreading or ascending, crown broad and irregular, young trees more pyramidal. Bark orange-brown, exfoliating in long stringy strips.
Often sparse with characteristically spreading, pendulous branchlets. Leaves borne in alternating whorls of usually 3.8–20mm long, 1.2mm wide, rigid and boat-shaped, straight with entire margins and pungent at apex, stomata in two conspicuously white bands occurring either side of the midrib on the upper surface.
Female cones 8–12mm, globose, borne in the axil of the leaves and orange-brown when mature in their second year. Male cones borne in the axils of the leaves, solitary or 1–2 per leaf whorl, 3–6mm long, 2–5mm wide, orange-brown.
Historically in the Canary Islands the wood was exploited for its valuable, aromatic timber, and used by local people in carpentry for a various items of furniture, construction and for making boxes because of the wood's capacity to deter insect pests (Vieira 2002). Today, due to its rarity and protected status, J. cedrus is not utilized. In Madeira the wood was also widely used and even as early as in the 15th century there were already concerns about the excessive cutting of this species. Restrictions on harvesting this species were ineffective; according to Silva and Menezes (1946) there were still some small woods of J. cedrus by the end of the 19th century, but the tree had almost vanished by the first decades of the 20th century. Today the wood is no longer used, unless it is taken from cultivated sources.
The plant is extensively cultivated as an ornamental and used by the forestry service particularly along the Laurissilva Levadas (man–made irrigation channels and pathways).