Rat Tail Cactus

How to care for Rat Tail Cactus

Light

Aporocactus flagelliformis thrives in a position with several hours of bright, direct sunlight each day. A south- or west-facing windowsill is ideal indoors. Some gentle morning sun is acceptable but prolonged harsh midday sun through glass in midsummer can scorch the stems; a little shade during the hottest part of the day prevents yellowing. Outdoors in summer the plant benefits from full sun in a sheltered spot.

Watering

Water moderately from spring through to early autumn, allowing the top centimetre or two of compost to dry out between waterings. Overwatering is the most common cause of failure and leads quickly to root and stem rot. From mid-autumn reduce watering significantly and keep the plant almost dry throughout winter, providing just enough moisture to prevent the stems from shrivelling. Resume regular watering as new growth appears in late winter or early spring.

Soil and potting

Use a free-draining cactus and succulent compost or mix standard potting compost with up to 50 per cent coarse grit or perlite. Good drainage is essential; the mix should never remain waterlogged. A slightly gritty, mineral-rich substrate mimics the rocky or bark-rich environments where the plant grows naturally.

Feeding

Feed once a month during the active growing season from spring through summer using a liquid fertiliser formulated for cacti and succulents, or a balanced fertiliser with a low nitrogen ratio (such as 5-10-10). High nitrogen encourages lush but weak stem growth at the expense of flowering. Do not feed during autumn and winter when the plant is resting.

Humidity and temperature

This species is tolerant of the dry air common in centrally heated homes and does not require misting or a humidity tray. Average household humidity of 40 to 60 per cent is perfectly adequate. It prefers temperatures between 15 and 27 C during the growing season. A cooler, drier winter rest period of around 7 to 13 C encourages bud set and better flowering the following spring; frost must be avoided as temperatures below 5 C can cause irreversible damage.

Repotting

Repot every two to three years in spring, or when roots are visibly escaping the drainage holes. Choose a container only one size larger than the current one, as this plant flowers more reliably when slightly pot-bound. Hanging baskets lined with coir or wire baskets suit the trailing habit well. Handle with care using folded newspaper or thick gloves, as the fine spines can cause skin irritation.

Pruning

Pruning is not strictly necessary but straggling or overly long stems can be trimmed back after flowering in early summer to maintain a tidy shape. Any dead or shrivelled stem sections should be removed cleanly with sterilised scissors or a blade to prevent rot spreading. Removed stem sections can be used as cuttings for propagation.

Is Rat Tail Cactus toxic?

Common problems

How to propagate

Stem cuttings

Cut a healthy stem section 10 to 15 cm long using a clean, sharp blade. Allow the cut end to callous over in a dry, bright spot for three to seven days, then insert the calloused end into slightly moist, gritty cactus compost. Roots typically develop within four to eight weeks.

Seed

Sow fresh seed on the surface of moist cactus compost in a tray or small pot, cover with a thin layer of fine grit, and place in a warm bright position at around 21 C. Germination can take two to four weeks; seedlings are slow growing and will take several years to reach flowering size.

Where Rat Tail Cactus comes from

Native to central Mexico, Hidalgo, Oaxaca, Guerrero.

Story and origins

The genus name Aporocactus is derived from the Greek word 'aporos', meaning difficult to pass or impenetrable, likely a reference to the densely spined, tangled mat of trailing stems. The species epithet flagelliformis comes from the Latin 'flagellum', meaning whip, and 'forma', meaning shape or form, describing the long, whip-like trailing stems that are the plant's most distinctive feature. Together the name evokes the impenetrable, whip-shaped growth habit that immediately distinguishes this cactus.

Aporocactus flagelliformis was introduced to European botanical cultivation in the seventeenth century and was one of the first cactus species to be widely grown as an ornamental in Britain and across Europe. It was formally described by the Swedish botanist Carl Linnaeus in 1753, who placed it in the genus Cactus before it was later reclassified. Its ease of cultivation and spectacular spring flowering made it a popular plant in Victorian conservatories and cottage windowsills alike. In recent decades taxonomic revisions have led some authorities to merge Aporocactus into the broader genus Disocactus, though the name Aporocactus flagelliformis remains the most widely used in horticulture.

Varieties to know

Aporocactus flagelliformis 'Tangerine'

A cultivar selected for orange-toned flowers rather than the typical cerise-magenta of the species.

x Aporophyllum hybrids

Intergeneric hybrids between Aporocactus and Epiphyllum, sometimes sold under the Aporocactus name, producing larger flowers in a wide range of colours; strictly speaking these are separate from the true species.

Fun facts

• The flowers of Aporocactus flagelliformis are adapted for pollination by hummingbirds in their native Mexican habitat.
• In the wild this cactus grows epiphytically, anchoring itself to trees and rocky outcrops rather than rooting in deep soil.
• The long trailing stems can reach well over 1 metre in length on a mature, well-grown specimen.
• Aporocactus flagelliformis has been cultivated in European greenhouses and conservatories since at least the seventeenth century, making it one of the oldest commonly grown cactus species in cultivation.
• Individual flowers last only a few days, but a healthy plant can produce dozens of blooms in succession throughout the spring flowering period.

Rat Tail Cactus FAQ