Synonyms:

Aloe retusa
Apicra retusa
Catevala retusa

Habitat:

Haworthia retusa is native to the Western Cape Province of South Africa, where it is particularly widespread in the Little Karoo region. It thrives in arid and semi-desert environments, growing mainly in rocky, well-drained areas, often in the shade of rock outcrops or low vegetation. Here it frequently grows partially buried, taking advantage of shallow depressions in the soil and crevices between rocks. This habitat creates a protected microclimate that softens direct sunlight and reduces the temperature fluctuations typical of the region.

Description:

The genus name Haworthia honors the English botanist and entomologist Adrian Hardy Haworth (1767-1833), one of the earliest scholars to study succulent plants in a systematic way. The specific epithet retusa derives from the Latin retusus, meaning “blunt” or “notched”, and refers to the characteristic shape of the leaves, often described as curving backward in a manner reminiscent of a thumb.

Known for its star-shaped rosettes, Haworthia retusa belongs to the genus Haworthia and to the family Asphodelaceae. It is a small, slow-growing succulent with a compact and well-defined habit. The rosettes are tight and regular, typically reaching about 8 cm (3 in) in diameter, and develop low to the ground, almost at soil level. The leaves are arranged in a spiral pattern, thick and fleshy, forming a dense structure that aids in water conservation. Light green to lime green in color, they often have a glassy or crystalline appearance, sometimes marked by fine longitudinal striations. The leaf tips are translucent and windowed, a distinctive feature that allows light to penetrate the plant and reach the internal photosynthetic tissues.

Flowering is subtle and understated, in keeping with the plant’s restrained appearance. Flowers usually appear from late spring to early summer, borne on a slender, elongated inflorescence that rises on an erect flower stalk reaching up to about 30 cm (12 in) tall. The individual flowers are small, tubular, and white, with delicate greenish or brownish-pink veins, opening successively along the stem. After flowering, the plant may produce small, dry capsule fruits containing numerous tiny seeds; however, fruiting is relatively rare in cultivation.

Cultivation:

Haworthia retusa is well suited for indoor cultivation thanks to its compact size, slow growth, and low light requirements.

It prefers a light, well-draining soil that prevents waterlogging. In cultivation, it adapts well to substrates formulated for succulents, ideally enriched with inert materials such as coarse sand, pumice, or lava rock.

Watering should be carried out sparingly, allowing the soil to dry out completely between waterings. During winter, irrigation should be further reduced, as the plant slows its growth and enters a resting phase.

It thrives in bright, indirect light. Direct sunlight, especially during the hottest summer months, can scorch the leaves and should therefore be avoided for prolonged periods. The species prefers a stable environment, with temperatures ranging between 10 °C and 30 °C (50-86 °F), and does not tolerate frost. In regions with cold winters, it is best grown in containers and moved indoors during the colder season.

A light feeding, using a well-diluted, balanced fertilizer, is sufficient once in spring and once in summer, during the active growing season.

Repotting is required only when necessary, generally every two to three years, due to the plant’s slow growth. This is best done in spring, using a slightly larger pot and a well-draining substrate.

This plant is considered non-toxic to humans and pets and can be grown indoors without special precautions.

It is a generally robust plant and is not particularly prone to disease when grown under proper conditions. The most common issues are related to excess moisture, which can lead to root rot. Possible pests include mealybugs and, more rarely, spider mites, especially in enclosed or poorly ventilated environments.

As a general guideline, Haworthia retusa should be placed in a bright but shaded location with good air circulation. It is best to avoid positioning it too close to glass surfaces or highly exposed walls, which can overheat during hot periods and cause stress to the plant.

Propagation:

Propagation of this species is generally easy and can be carried out in several ways. The most common and effective method is the separation of offsets, which develop naturally at the base of the mother plant and allow new specimens to be obtained relatively quickly. Propagation can also be achieved through leaf cuttings by removing a healthy leaf and allowing it to dry for several weeks so the wound can callus, then placing it on the substrate with the base slightly buried; roots and small rosettes may form within one or two months. Seed propagation is also possible, although it is less commonly used in cultivation as it is slower and more demanding.

Curiosity:

One of the most distinctive features of this species is its translucent, “windowed” leaves. This characteristic allows light to penetrate into the plant and reach the internal photosynthetic tissues even when the rosette grows almost entirely at ground level. It is an evolutionary adaptation typical of plants living in arid, brightly lit environments, enabling the plant to reduce direct sun exposure and protect itself from heat and dehydration while maintaining efficient photosynthesis.

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