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PlantFiles: Ferocious Blue Cycad
Encephalartos horridus

Family: Zamiaceae
Genus: Encephalartos (en-sef-uh-LAR-tos) (Info)
Species: horridus (HOR-id-us) (Info)

Synonym:Zamia horrida

8 members have or want this plant for trade.

Tropicals and Tender Perennials

36-48 in. (90-120 cm)

4-6 ft. (1.2-1.8 m)

USDA Zone 9a: to -6.6 C (20 F)
USDA Zone 9b: to -3.8 C (25 F)
USDA Zone 10a: to -1.1 C (30 F)
USDA Zone 10b: to 1.7 C (35 F)
USDA Zone 11: above 4.5 C (40 F)

Sun Exposure:
Full Sun

Seed is poisonous if ingested
All parts of plant are poisonous if ingested
Plant has spines or sharp edges; use extreme caution when handling

Bloom Color:

Bloom Time:

Grown for foliage

Other details:
Drought-tolerant; suitable for xeriscaping
This plant may be considered a protected species; check before digging or gathering seeds

Soil pH requirements:
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)

Patent Information:

Propagation Methods:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
From seed; germinate in vitro in gelatin, agar or other medium

Seed Collecting:
Unknown - Tell us

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3 positives
2 neutrals
No negatives

Gardeners' Notes:

Positive palmbob On Sep 29, 2013, palmbob from Acton, CA (Zone 8b) wrote:

Many confuse this species with Encephalartos trispinosus or Encephalartos arenarius blue, both very similar plants. Of the three, this one tends to be the smallest over all, and usually much less robust than E arenarius. Leaves of all three tend to be pale bluish and have multiple spines. But E horridus leaves have a 90 degree twist to them the other two do not tend to have. E arenarius leaves are much wider and have a lot more surface area than the other two, and the blue forms are quite blue, while E horridus tends to be much whiter to pale blue-green (greenish in humid climates). E trispinosus leaves do not have the twist, and usually have three spines (as opposed to 4 of horrid us), but there are so many variations of each species, this is not always a good characteristic to use. E horridus leaves have a tendency to arch strongly, sometimes nearly to the point of forming a full circle, which is not a common characteristic of E trispinosus and ext. rare in E arenarius. E trispinosus tends to be a faster plant and more tolerant of abuse than E horridus, but all three are fairly easy to grow in the proper climate.

Positive Lightray On Oct 23, 2012, Lightray from Carlsbad, CA (Zone 10a) wrote:

The attractive blue color is a nice addition to the garden. One of the easier to grow of the blue cycads if it gets sufficient sun and good draining soil. I get good blue color even within half a mile of the beach in North San Diego County, where we often see May Gray and June Gloom to start the summer.

Positive BayAreaTropics On Oct 30, 2011, BayAreaTropics from Hayward, CA wrote:

This is a sun worshipping plant. If you dont have a spot that gets near sun up to sundown light,it will not do well. I have a plant that looks to be a seedling but is already four years old+ with a stubby (and now exposed by accident due to its pot being knocked over) caudex that is trying to push out a single frond. It's a long story of trial and many errors with an expensive,delicate plant.
But-think of it as a light needy cacti and you are much closer to having them do well,then thinking of it as a Sago or wet climate cycad.

Neutral Cretaceous On Jun 21, 2007, Cretaceous from El Sobrante, CA (Zone 9b) wrote:

Encephalartos horridus is native to Cape Province, South Africa.

It grows in dry, desert-like scrub and bush habitat, where annual rainfall is 10-24 inches.

Encephalartos are listed on CITES Appendix I.

Neutral BotanyBob On May 29, 2001, BotanyBob from Thousand Oaks, CA wrote:

This plant belongs to the Gymnosperms (cone-forming plants) though it's really not very closely related to most other Gymnosperms like pines. It looks a lot more like a palm than anything else. Typical to most other cycads, this plant has a short, succulent trunk full of starch, which is the 'life's blood' of the plant. The roots can be hacked off, as can the leaves and cones, and as long as the trunk, or caudex as it's called, is intact, it will usually recover. This characteristic makes this plant relatively easy to transplant.

Originally from Southern Africa, E horridus is a very spiny and interesting plant, having bizarrely twisted leaves that erupt out of the top of the caudex (sort of palm-like) and incredibly spiny, stiff, blue leaflets (hence the 'ferocious' name). This species is a highly sought collectors item and larger specimens are often sold for thousands of dollars. It is also very slow growing and it can take decades for a seedling to mature to the point of coning.

Like most cycads, overwatering may cause rotting of the caudex, especially if the soil is not very pourous. This species is particularly drought tolerant and can go many months without any water, as long as the caudex is healthy. Cycads with this bluish coloration seem to be the most tolerant of full sun and intense heat, and are slightly more tolerant of frost, too (this plant can easily tolerate temps in the mid 20s for a short time). However, cold, wet winters in moisture-retaining soils may rot the plant. Also humid climates are tough on the bluer cycads and they tend to wither in climates similar to southern Florida or Hawaii. Southern California and Arizona climates are perfect for this species.

Fertilizing is routine. Most cycads can tolerate quite a bit of fertilizer, though they can be burned by too much (especially if granules are dropped into the crown of the plant).
Fertilization occurs in nature by having insect vectors pollinate the female cones after being on the male cones. In cultivation there are no suitable pollinators ( in the US, at least) so all pollinating must be done by hand. Eventually plants sucker or 'pup'. These pups can be cut off the main plant and rooted in pumice, though care must be taken not to overwater these pups or they will easily rot.


This plant has been said to grow in the following regions:

Mesa, Arizona
Phoenix, Arizona
Carlsbad, California
El Cerrito, California
Encinitas, California
Hayward, California
Reseda, California
Spring Valley, California
Thousand Oaks, California
Tulare, California
Visalia, California
Naples, Florida

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