The Selenicereus anthonyanus, known as the Fishbone Cactus, Zig-Zag Cactus, or Ric-Rac Cactus, is a distinctive plant. Its common names describe its unique appearance: flattened, deeply lobed stems resembling a fish’s skeleton or a zigzag pattern. Native to southern Mexico’s tropical rainforests, this epiphytic cactus is popular for its unusual foliage and spectacular, fragrant night-blooming flowers.
Essential Care Guidelines
Light Needs
The Fishbone Cactus thrives in bright, indirect light, mimicking its natural habitat where it grows beneath a tree canopy. Placing it near an east or west-facing window indoors provides ideal conditions. Too much direct sunlight, especially harsh afternoon sun, can cause scorching and browning of the stems. Insufficient light may result in leggy growth and a lack of flowering.
Watering Techniques
Unlike many desert cacti, the Selenicereus anthonyanus prefers consistent moisture during its active growing season (spring through summer). Water thoroughly until water drains from the pot’s bottom, then allow the top 1 to 2 inches of soil to dry before watering again. Overwatering can lead to root rot, so proper drainage is important. During winter, when growth slows, significantly decrease watering frequency.
Ideal Soil Mix
As an epiphyte, the Fishbone Cactus naturally grows on trees, absorbing nutrients and moisture from the air and organic debris. It requires a well-draining, airy potting mix rich in organic matter. An ideal blend includes commercial cactus or succulent soil combined with perlite, orchid bark, or peat moss to enhance drainage and aeration. This mix prevents waterlogging, promoting root health.
Temperature and Humidity
This tropical cactus prefers warm, humid environments, similar to its native rainforest. An indoor temperature range between 60°F and 80°F (15.5°C to 27°C) is suitable. It is sensitive to temperatures below 50°F (10°C), which can cause damage. Humidity levels above 60% are beneficial, though the plant adapts to average household humidity. Misting or using a pebble tray can increase ambient humidity.
Feeding Schedule
Regular fertilization supports growth and encourages blooming. During spring and summer, apply a balanced, water-soluble fertilizer diluted to half strength every 4 to 6 weeks. Some sources suggest using a fertilizer higher in potassium in early spring for flower production, then switching to a balanced formula by mid-summer. Stop fertilizing during fall and winter when growth slows or the plant enters dormancy.
Potting and Repotting
Repotting a Fishbone Cactus is necessary every two to three years, or when the plant becomes root-bound. Signs include roots growing out of drainage holes or the plant appearing too large for its container. Choose a pot only slightly larger (about two inches wider) to prevent issues like root rot from excess soil moisture. Terracotta pots are a good option; their porous nature allows for better air circulation and moisture evaporation, preventing overly wet soil.
When repotting, carefully remove the plant and gently loosen any circling roots. Place fresh, well-draining soil mix at the bottom of the new pot, then position the plant at the same depth. Fill around the roots with more soil, gently compacting it. After repotting, wait a few days before the first watering to allow the plant to recover from transplant shock.
Multiplying Your Plant
Propagating Selenicereus anthonyanus is straightforward, most commonly achieved through stem cuttings. Select a healthy stem segment 4 to 6 inches long, using sharp, clean scissors or pruning shears. Allow the severed end to dry and form a callus for at least 24 hours, or ideally a few days, in a cool, dry location. This callusing step prevents rot when the cutting is planted.
Once callused, plant the cut end into a small pot filled with a lightly moistened, well-draining potting mix. Keep the mix consistently moist but not soggy to encourage root development. Place the cutting in bright, indirect light for optimal rooting. Roots typically form within a few weeks; once new growth appears, care for the young plant like a mature specimen.
Troubleshooting Common Problems
Overwatering frequently causes issues for the Fishbone Cactus, leading to yellowing or mushy stems and root rot. If these symptoms appear, allow the soil to dry more thoroughly between waterings and ensure adequate drainage. If root rot is extensive, removing affected portions and propagating healthy cuttings may be necessary.
Shriveled or crispy stems indicate underwatering or insufficient humidity. Increase watering frequency slightly or enhance humidity through misting or a pebble tray. A lack of new growth or flowers often points to insufficient light or nutrients. Move the plant to a brighter spot with indirect light and ensure a regular feeding schedule during the growing season to promote vigorous development and blooming.
Pests such as mealybugs, spider mites, and fungus gnats can affect Selenicereus anthonyanus. Mealybugs and spider mites are attracted to low humidity, while fungus gnats appear in overly moist soil. Treat affected plants with appropriate horticultural sprays or insecticidal soap. Good air circulation and proper watering practices also help prevent pest issues.