Fishbone Cactus

How to care for Fishbone Cactus

Light

Bright, indirect light suits this plant best throughout the year. A position near an east- or west-facing window is ideal; it can tolerate a couple of hours of gentle morning sun but harsh afternoon sun will bleach and scorch the stems. Being an epiphyte from shaded forest canopies, it does not require or appreciate the intense direct sun that desert cacti need. In low light the stems may become elongated and pale, and flowering is unlikely.

Watering

As an epiphytic cactus, Disocactus anguliger is more sensitive to overwatering than most people expect from a cactus, yet it still requires more consistent moisture than desert-dwelling species. During spring and summer, water thoroughly when the top third of the compost feels dry, allowing excess to drain freely. Reduce watering in autumn and winter to encourage the flowering response, keeping the compost barely moist rather than wet. Always use room-temperature water and avoid leaving the pot sitting in a saucer of water.

Soil and potting

A free-draining mix that retains slight moisture without becoming waterlogged is essential. A ready-made cactus or orchid compost blended with an equal part of perlite works well. Adding a small amount of coarse bark or coconut coir improves aeration and mimics the plant's natural growing medium of decomposed organic matter on tree branches. Avoid heavy, peat-dense composts that compact easily and impede drainage.

Feeding

Feed once a month from spring through to late summer using a balanced liquid fertiliser diluted to half the recommended strength, or a fertiliser with a low nitrogen formulation to avoid excessive soft growth at the expense of flowers. A high-potassium feed applied once or twice in late summer can support bud development. Do not feed during autumn and winter when the plant is resting.

Humidity and temperature

Preferring the humid conditions of its forest habitat, this plant thrives at 50-60% relative humidity. Grouping plants together, placing the pot on a tray of damp gravel, or using a cool-mist humidifier are all effective ways to raise humidity around the plant. Average room temperatures of 15-27 C are suitable during the growing season. A cooler period of 10-15 C in autumn helps trigger flowering. Temperatures below 10 C should be avoided, and the plant must be kept well away from cold draughts and radiators.

Repotting

Repot every two to three years, or when roots begin to emerge from the drainage holes. Choose a pot only one size larger, as this plant blooms more reliably when slightly root-bound. Repotting is best carried out in spring. A hanging basket or a pot that allows the stems to trail or cascade shows the plant to best advantage and suits its naturally pendulous growth habit.

Pruning

Pruning is not routinely required but can be carried out to remove any shrivelled, damaged, or excessively long stems, or to maintain a tidy shape. Simply cut back a stem to a convenient joint using clean, sharp scissors or a blade. Removed sections can be used as cuttings for propagation. Avoid heavy cutting immediately before or during the flowering period.

Is Fishbone Cactus toxic?

Common problems

How to propagate

Stem cuttings

Cut a healthy stem segment of 10-15 cm at a joint using a clean, sharp blade and allow the cut end to callous for 24-48 hours. Insert the calloused end shallowly into a barely moist mix of perlite and cactus compost, and place in bright indirect light at around 20 C. Roots typically develop within 3-6 weeks.

Seed

Sow fresh seed in spring on the surface of a moist, fine cactus compost and cover the tray or pot loosely with a clear plastic bag to retain humidity. Germination can take several weeks and is unreliable; seedlings grow slowly and take several years to reach a mature, flowering size.

Where Fishbone Cactus comes from

Native to southern Mexico, Guatemala.

Story and origins

The genus name Disocactus derives from the Greek 'dis', meaning twice or double, and 'kaktos', the ancient Greek word for a spiny plant; the intended sense relates to distinguishing features of the genus within the broader cactus family. The species epithet anguliger comes from the Latin 'angulus', meaning angle or corner, and 'gerere', meaning to bear or carry, describing the plant's strongly angled, lobed stems that are its most visually defining characteristic.

Disocactus anguliger was first formally described in 1858 by the German botanist Joseph Gerhard Zuccarini, based on specimens collected from the montane forests of Mexico. It was placed in various genera over the subsequent century and a half, including Phyllocactus and Cryptocereus, before taxonomic revisions consolidated it within Disocactus. The species gained popularity as a houseplant in Europe and North America during the latter half of the twentieth century, valued for its architectural form and the novelty of its nocturnal flowers. It has no significant recorded cultural or medicinal history among indigenous Mexican communities, unlike some of its better-known relatives in the Cactaceae family.

Varieties to know

Disocactus anguliger (straight species)

The widely cultivated standard form with deeply lobed, mid-green stems and pale yellow to white fragrant nocturnal flowers.

Cryptocereus anthonyanus (synonym)

An older synonym still encountered in the horticultural trade; plants sold under this name are the same species.

Fun facts

• The flowers of Disocactus anguliger are nocturnal, opening after dark and closing by morning, and are pollinated in the wild by moths and bats attracted to their sweet fragrance.
• Despite being classified as a cactus, this species has no true spines; instead, it has small, fine bristles called glochids in its areoles that are far less prominent than those of desert cacti.
• In its native Mexican habitat it grows entirely as an epiphyte, anchoring itself to the branches and crevices of trees without parasitising the host, drawing moisture and nutrients from rain, mist, and decomposing organic debris.
• The common name 'Ric Rac Cactus' refers to the ric-rac ribbon, a flat, zigzag-edged braid used in sewing and dressmaking, which the stems closely resemble.
• Individual flowers are short-lived, typically lasting only a single night, so growers who wish to see them in bloom need to check the plant after dark during the autumn flowering period.

Fishbone Cactus FAQ