Selenicereus anthonyanus (Fishbone Cactus)

Selenicereus anthonyanus, commonly known as the Fishbone Cactus, Ric Rac Cactus, or Zig Zag Cactus, is a unique and eye-catching species. Its distinctive stems resemble a fish’s skeleton or a zigzag pattern, making it a popular choice among plant collectors and indoor gardeners. It is a night-blooming cactus that produces large, fragrant flowers that open during the night and add an exotic appeal to any collection.

Selenicereus anthonyanus is often confused with Epiphyllum anguliger, another plant commonly known as Fishbone Cactus, but they are distinct species with similar appearances.

The Fishbone Cactus is a member of the Cactaceae family, which also includes the popular Chrismas cactus, prickly pear (opuntia), pincushion cactus (mammillaria), and the iconic saguaro cactus and San Pedro cactus.

Description

Selenicereus anthonyanus is admired for its flattened, deeply lobed stems, which have a zigzag or fishbone-like appearance. These unusual stems make it stand out from typical cacti, giving it a striking and ornamental appeal. The stems are green, thick, and fleshy, designed to store water, as with most cacti, and are often mistaken for leaves due to their unique shape.

Another standout feature is its large and fragrant nocturnal flowers, which bloom only at night and wilt by morning.

Native Habitat

The Fishbone Cactus is native to the tropical rainforests of southern Mexico, where it thrives in warm, humid environments. In its native habitat, it grows as an epiphyte, often clinging to the bark of trees in the forest canopy. It is well-adapted to the dappled light and high humidity of tropical regions.

Plant Type and Habit

This cactus is a fast-growing, tender perennial epiphyte with a sprawling, trailing growth habit. It is ideal for hanging baskets or as a climbing plant. As an epiphyte, it grows best in well-drained soil or mounted on surfaces where it can climb or hang.

Plant Size

This is a medium-sized cactus. Its stems can grow 3-6 feet (90-180 cm) long and are typically 3-6 inches (7-15 cm) wide.

Cactus Flowers

The flowers of the Fishbone Cactus are truly spectacular. They are large, measuring up to 6-8 inches (15-20 cm) in diameter, and are typically white to pale yellow with delicate, slender petals. The flowers are fragrant and bloom only at night, remaining open for just a few hours before wilting by morning.

These nocturnal blooms are pollinated by moths and bats in their native habitat, which is why they bloom in the evening. The large flowers open quickly at dusk, and their sweet fragrance attracts nighttime pollinators.

They typically bloom in late spring or early summer, although the exact timing can vary depending on growing conditions. The blooming period usually lasts only a few days, with each flower lasting just a single night.

Fruit

After blooming, this cactus produces small, round, red fruits. The fruits contain small seeds and are enjoyed by wildlife, such as birds and small mammals, in their native habitat.

Stem and Spines

The cactus’s most recognizable feature is its stems. They are flattened, green, and deeply lobed, creating a zigzag pattern that resembles a fishbone, hence its common name. The stems grow 3-6 inches (7-15 cm) wide and are designed to store water, making the plant drought-tolerant.

Unlike many other cacti, Selenicereus anthonyanus has few or no spines. Instead, its stems are relatively smooth, with only small, hair-like structures at the areoles where spines would typically grow.

Hardiness

Selenicereus anthonyanus is hardy in USDA zones 10-12, meaning it prefers warm temperatures and cannot tolerate frost. The plant thrives in temperatures between 50°F to 85°F (10°C to 29°C), making it suitable for indoor growing or tropical climates.

It should be protected from temperatures below 50°F (10°C) if grown outdoors, as it is not cold-hardy. It is best grown as an indoor plant or moved indoors during colder months in cooler climates.

Uses

The Fishbone Cactus is primarily grown for its ornamental value. Its unusual, zigzag-shaped stems and night-blooming flowers make it a popular choice for indoor gardening, where it can be displayed in hanging baskets or allowed to climb on trellises or other supports.

The cactus is also used in epiphytic plant collections and makes a dramatic addition to tropical-themed gardens or displays. It is ideal for adding a touch of the exotic to living walls, indoor greenhouses, or bathrooms where humidity levels are high.

Wildlife

In its native habitat, Selenicereus anthonyanus attracts moths, bats, and other nocturnal pollinators that are drawn to its fragrant, night-blooming flowers. Additionally, the small fruits are consumed by birds and small mammals, which help with seed dispersal.

Toxicity

Selenicereus anthonyanus is not known to cause harm to humans and pets, making it a safe choice for households with children or animals. However, it is always a good idea to keep the plant out of reach of curious pets, as ingesting large quantities of plant material could cause digestive upset.

Drought Tolerance

Although native to tropical rainforests, the Fishbone Cactus is surprisingly drought-tolerant due to its ability to store water in its fleshy stems. It can survive periods of dryness but will perform best with regular watering, especially during the growing season.

Invasiveness

The Fishbone Cactus has naturalized in the Galapagos Islands and possibly Brazil, with potential for naturalization on Maui and Hawaiʻi Island. Its ability to thrive in shaded tropical ecosystems, combined with its rapid growth and vegetative reproduction, makes it a potential invasive species risk.

Benefits

The primary benefits of the Fishbone Cactus are its ornamental appeal and ease of care. Its unique fishbone-shaped stems make it a standout in any plant collection, and its night-blooming flowers add an exotic touch to indoor gardens. Additionally, its ability to thrive in low light and high humidity environments makes it a great choice for bathrooms, living walls, and tropical-themed spaces.

Fishbone Cactus Care

The Fishbone Cactus is a unique, easy-to-care-for plant that thrives both indoors and outdoors in warm, humid environments. Here’s how to grow and care for this striking cactus:

Light

• For optimal growth, provide bright, indirect light. It thrives near an east-facing window or in areas with filtered sunlight.
• The Fishbone Cactus can also tolerate low light conditions, making it suitable for bathrooms or dimmer spaces, though growth will be slower.

Soil

• Use a well-draining soil mix such as a cactus or succulent potting mix. You can add perlite or orchid bark to improve drainage and mimic its natural epiphytic environment.
• The Fishbone Cactus thrives in slightly acidic to neutral soil, with a pH between 6.0-7.0.

Watering

• Water thoroughly, but allow the soil to dry out slightly between waterings. The Fishbone Cactus prefers consistent moisture but should not sit in soggy soil.
• In summer, water more frequently, but reduce watering during the winter when the plant is dormant.

Humidity

• The Fishbone Cactus prefers high humidity (around 50% or more). If growing indoors, mist the plant or use a humidifier to increase moisture, especially during dry seasons.

Temperature

• The ideal temperature range is between 50°F to 85°F (10°C to 29°C). It is not frost-tolerant, so keep it indoors if temperatures drop below 50°F (10°C).

Fertilizer

• During the growing season (spring and summer), feed the Fishbone Cactus with a balanced, water-soluble fertilizer every 4-6 weeks. Dilute the fertilizer to half strength for best results.
• Avoid fertilizing in winter when the plant is dormant.

Pruning

• Minimal pruning is required. You can trim back any overgrown or damaged stems to encourage new growth and maintain its shape.

Propagation

• The Fishbone Cactus is easily propagated by stem cuttings. Cut a healthy segment and allow it to callous for a few days before planting in well-draining soil.

Pests and Diseases

• Mealybugs, spider mites, and scale insects can occasionally affect the Fishbone Cactus. Treat infestations with insecticidal soap or neem oil.
• Ensure proper drainage to prevent root rot  from overwatering.