Common Problems With Fishbone Cactus and How to Handle Them
Decode the visual cues of your fishbone cactus. This guide helps you understand what its unique stems are telling you about its health and happiness.
The fishbone cactus, known scientifically as Disocactus anguliger, is a popular houseplant admired for its uniquely shaped stems that resemble a fish skeleton. This epiphytic cactus, native to the jungles of Mexico, has a trailing growth habit that makes it an excellent choice for hanging baskets. While generally considered a low-maintenance plant, it can display signs of distress when its specific needs are not met.
Stem Discoloration
One of the most visible signs of a problem with a fishbone cactus is a change in the color of its stems. Yellowing foliage is often the first indicator of overwatering. When the soil remains waterlogged, the roots cannot access oxygen, leading to dull, yellow, and often soft stems. To correct this, feel the top 2-3 inches of soil; if it is damp, withhold water until it has completely dried out. A pot with functional drainage holes is necessary to prevent water from pooling at the root level.
Brown markings on the stems can point to environmental issues. If you notice dry, crispy brown spots, the cause is likely sunburn from exposure to harsh, direct sunlight. Conversely, if the tips of the stems are turning brown and appear shriveled, the plant is not receiving enough water. Soft, dark brown or black spots, however, may signal a more serious fungal infection, which can arise from consistently over-saturated soil.
A red or purple tinge along the edges of the stems is a reaction to high levels of light. This change in pigmentation is a natural stress response and is not harmful to the plant’s health. It indicates that the cactus is receiving the maximum amount of light it can process. If the coloration is undesirable, moving the plant further from its light source will cause the stems to revert to their normal green color.
Changes in Stem Texture
Mushy or soft stems are a clear sign of root rot. This condition is caused by overwatering, where the roots begin to decay in the overly moist soil. To address this, you must unpot the plant and inspect the root system. Healthy roots will be firm and yellowish, while rotten roots will be brown, black, and soft. Using sterile scissors, carefully trim away all affected roots before repotting the cactus in a fresh, well-draining soil mix.
Stems that appear wrinkled, limp, or shriveled are signaling dehydration. This occurs when the plant is underwatered, causing the cells in the stems to lose turgor pressure. You can confirm this by checking the soil, which will likely be completely dry throughout the pot. The solution is to give the plant a thorough watering, allowing water to flow until it freely drains from the bottom of the pot.
Common Pest Infestations
The fishbone cactus can be susceptible to certain pests. Mealybugs appear as small, white, cotton-like masses, clustered in the joints where the stem segments meet, while scale looks like small, hard, brown bumps attached to the stems. For isolated infestations of either mealybugs or scale, you can dip a cotton swab in isopropyl alcohol and manually remove the insects.
Larger infestations may require more comprehensive treatment. Spider mites are tiny arachnids whose presence is revealed by fine, delicate webbing on the plant. A widespread outbreak of these pests can be managed by spraying the entire plant. Using a pre-formulated insecticidal soap or neem oil solution according to the product’s directions is an effective way to control these pests.
Failure to Bloom
A healthy, mature fishbone cactus produces fragrant flowers that bloom at night, but getting it to this stage requires specific conditions. One of the primary reasons for a lack of flowers is insufficient light. The plant needs several hours of bright, indirect sunlight each day for bud production. Placing it near an east or west-facing window is ideal.
Another factor is the plant’s need for a winter dormancy period. The cactus requires a rest period during the cooler months. This involves reducing watering and keeping the plant in a slightly cooler environment. Fertilization is also a factor; applying a fertilizer high in phosphorus during the spring growing season can promote flowering. Finally, a young plant may simply not be mature enough to bloom, a process that can take several years.