Sisal

Agave sisalana

NEMBA: Category 2

English: Sisal, Agave, Century Plant, Hemp Plant, Mescal, Sisal Agave, Sisal Hemp

Historical scientific names: Agave rigida var. sisalana

Agave sisalana, commonly known as sisal, is a robust succulent native to Mexico that has become widely cultivated for its strong fibres. This large, spiky plant forms a dense rosette of thick, long, grey-green leaves with sharp margins and a prominent terminal spine, growing up to 2 meters tall.

Commercially important for producing sisal fibre used in rope, twine, and various textiles, it has also become an invasive species in many parts of the world, spreading aggressively in grasslands and disrupting local ecosystems.

Have you got a better picture?

If you don't mind us using it, please upload it by clicking the Upload button below (you must be logged in to do this)

Origin:

Thought to originate from the Yucatán Peninsula in Mexico.

Distinguishing features:

Large, stiff, sword-shaped, grey-green leaves arranged in a dense, upright rosette.
Leaves typically have a sharp terminal spine and may have small, sharp teeth along the margins.
Produces a very tall, straight flowering stalk (mast) that can reach several metres high.

Overall appearance:

A robust, stemless or short-stemmed perennial succulent forming a large, dense rosette of long, rigid leaves.

Height:

The rosette itself typically reaches 1 to 2 metres in height. The impressive flowering stalk can extend much higher, usually 4 to 6 metres tall.

Width:

The rosette can spread approximately 1 to 2 metres wide.

Leaves:

Long, stiff, and sword-shaped, ranging from 1 to 1.5 metres in length and about 10 to 15 centimetres wide. They are typically grey-green or bluish-green, though sometimes they can be paler. Each leaf culminates in a strong, sharp, dark brown or black spine about 2 to 3 centimetres long. Some varieties may have small, sharp teeth along the leaf margins, while others are spineless along the edges. The leaves are very fibrous.

Flowers:

Pale yellow to greenish-white, about 4 to 6 centimetres long, and appear in large, branched clusters (a panicle) at the very top of the tall central flowering stalk. The plant is monocarpic, meaning it flowers only once after many years (typically 7-15 years), and then the main rosette dies, though it often produces numerous suckers (offsets) from its base. The flowers are generally hermaphroditic, containing both male and female reproductive organs.

Flowering season:

In South Africa, flowering generally occurs in spring to summer, roughly from October to February, though this can vary.

Fruits:

Small, oblong, three-sided capsules, up to 6 centimetres long, which develop after successful pollination. However, fruit set is often low, and the plant primarily reproduces through bulbils (plantlets) produced on the flower stalk.

Seeds:

Small, flattened, D-shaped, and black. They are contained within the fruit capsules but are less commonly produced than bulbils, which are the primary means of long-distance dispersal for this plant.

Bark:

The plant has a very short, stout stem or "trunk" that becomes visible as older, lower leaves die and fall off. This stem is covered in the persistent bases of old leaves rather than true bark.

Thorns:

A prominent, sharp, dark-coloured spine (terminal spine) is present at the tip of each leaf, approximately 2 to 3 centimetres long. Some varieties also have small, sharp, recurved teeth along the leaf margins, though cultivated forms are often selected to be unarmed on the edges.

Wood:

The plant has a succulent, fibrous stem, not true woody tissue.

Roots:

It has a fibrous root system that is relatively shallow but extensive, allowing it to efficiently absorb moisture from the upper soil layers.

Soil type:

Highly adaptable to various soil types, preferring well-drained, sandy loams. It thrives even in poor, rocky, or degraded soils and is very tolerant of drought conditions. It does not tolerate waterlogging.

Aspect:

Prefers full sun and performs best in open, sunny locations. It is highly drought-tolerant and thrives in warm, dry climates.

Ediblity:

The plant is not generally considered edible for humans. While some agave species are used for sweeteners or alcoholic beverages, Agave sisalana is cultivated for its fibre. The sap can cause skin irritation or dermatitis in some individuals.

Toxicity:

The sap of Agave sisalana can cause skin irritation, itching, redness, and blisters in sensitive individuals due due to the presence of calcium oxalate crystals. It is not intended for consumption.

Uses:

Its primary use globally, including historically in South Africa, is for its incredibly strong and durable natural fibre, known simply as "sisal." This fibre is used to make ropes, twine, baler twine, mats, carpets, sacking, dartboards, polishing cloths, and even paper. The waste material from fibre extraction can be used for biofuel or animal feed.

Ecology:

As an alien invasive plant in South Africa, Agave sisalana can form dense, impenetrable stands, particularly in disturbed areas, roadsides, and abandoned plantations. These dense thickets can outcompete and displace indigenous vegetation, reducing biodiversity and hindering the movement of wildlife. Its flowers, when produced, can attract generalist pollinators like bees and moths.

Distribution and habitat:

Widely cultivated across warmer, drier regions of South Africa for its fibre, it has extensively escaped cultivation and become naturalised. It is a problematic invader in several provinces, notably KwaZulu-Natal, Eastern Cape (including areas around Kenton-on-Sea), Limpopo, and Mpumalanga. It thrives in semi-arid and subtropical climates, often found invading savannas, grasslands, coastal bush, and degraded areas.

Derivation of name:

The genus name Agave comes from the Greek word 'agavos', meaning "noble" or "illustrious," referring to the stately appearance of the flowering plant, especially when in bloom.
The species epithet sisalana refers to the port of Sisal in the Yucatán Peninsula, Mexico, which was historically the main shipping point for sisal fibre.

Historical aspects:

Sisal was introduced to South Africa for commercial fibre production, particularly during the 19th and 20th centuries, as a valuable export commodity. Large plantations were established, particularly in the Eastern Cape and KwaZulu-Natal. The plant's hardiness and ability to grow in poor soils made it attractive for cultivation, but also contributed to its invasive spread when plantations were abandoned or left unmanaged.

Interesting facts:

Forget cotton or wool, this plant is a master of natural fibres! Its tough leaves are packed with super-strong threads that have been used to make everything from sturdy ropes for ships to fancy dartboards.
If you ever see one of these towering giants in full bloom, consider yourself lucky! It's a "grand finale" act – the main plant only flowers once in its entire life, after many years of growing, before it decides its work is done and fades away.
Don't mourn for long though! Before it says goodbye, it often sprouts dozens of tiny "baby plants" (called bulbils) right on its flowering stalk, ready to start new generations.
It's so good at surviving that it can grow in places where most other plants give up, like really dry, hot spots.