Origin and Habitat: Port Elizabeth (extinct) and Uitenhage district, Eastern Cape Province,South Africa.
Altitude range: Occurs from 328-1,312 ft (100-400 m) above sea level.
Habitat and ecology:Encephalartos horridus usually occurs in dense thorny scrub, on deep fertile soil and open rocky quartzite ridges. The climate is warm year round, average annual rainfall in the range of 9.8-23.6 in (250-600 mm) per annum and summer temperatures up to 104°F (40°C). The now extinct subpopulations north and west of Port Elizabeth probably occurred in Sandstone Fynbos. E. horridus is now extinct in several parts of its former range where it has been totally eliminated by urban development. Substantial numbers have also been removed by collectors in the past 50 years. It is difficult to estimate what proportion of plants have disappeared but it could be as high as 50%. Cycads have few natural enemies, however in the wild they can be subject to predation from animals such as porcupines, baboons and certain insects. Although the Eastern Cape Blue Cycad can reproduce by suckering, more commonly reproduction requires insect pollination. Once seed cones have been pollinated seeds are spread by animals that eat the fleshy cones. Encephalartos horridus are now available as a result of commercial distribution in nurseries and gardens throughout the world.

Cultivation and Propagation: Encephalartos horridus is an adaptable plant well suited to warm temperate and subtropical climates, and can handle light frosts. It can be grown in full sun without its leaves burning. Its beauty and ease of horticulture make it one of the finest cycads for use in the garden. As a garden plant, this cycad will usually hold one or two crowns of leaves, all in good condition.As a seedling, it often loses its previous year's leaves before the new leaves emerge. The seedlings need plenty of room for the tap root to develop and require very good drainage.
Growth rate: It is a long lived slow growing plant taking 15 to 20 years for one of these to produce a cone, so patience is a must.
Soils: It responds well to deep, fertile, slightly acidic, well drained, soil enriched with compost.
Waterings: In cultivation prefers plenty of water, especially in dry weather for optimal growth. But it is eventually drought resistant.
Fertilization: Naturally undemanding for nutrients, it responds very well to regular applications of fertilizer. Growth can be greatly improved through the application of fertilizers. Most growers find that a fertilizer having an even NPK (Nitrogen, Phosphorus, Potassium) balance, and supplemental trace elements, provides a good start for cycads.
Exposure: It will grow in partial shade, however best results are obtained growing the seedlings in full sun.
Warning: Seeds are poisonous.
Hardiness: They do best in a tropical or subtropical climate and should be kept totally dry in winter at or around 50°F (10°C) but demonstrate a remarkable degree of cold resistance and may tolerate light frost for short periods if dry, however heavy frosts would probably be fatal.
Propagation: Plants are available from nurseries in many areas, however they are also easy to propagate from seeds. They can also be propagated from suckers with some patience and experience.