The Rhino Plant, or Pachypodium horombense, is a captivating succulent. Its unique form, characterized by a swollen trunk and spiny branches, makes it a fascinating specimen.
Understanding the Rhino Plant
The Rhino Plant originates from the Horombe plateau in southern Madagascar. This succulent shrublet grows up to 1.5 meters tall, developing a plump, bottle-shaped main stem. Its botanical name, “Pachypodium,” means “thick foot,” referring to its swollen base, or caudex, which stores water, allowing it to endure arid conditions.
The plant’s trunk and branches are adorned with short, paired spines, giving it a cactus-like appearance. Rosettes of thick, stiff, elliptic to narrowly oblong leaves emerge from the branch tips. These leaves are deep green and glossy on the upper surface, with paler undersides. During warm months, Pachypodium horombense produces striking yellow, broadly cup-shaped flowers that bloom on long stalks above the foliage.
Essential Rhino Plant Care
Light Needs
Pachypodium horombense thrives with abundant light, preferring full sun exposure. Placing it in a location that receives several hours of unfiltered, direct sunlight daily is optimal for its growth and flowering. While it can tolerate partial sun, lower light conditions can lead to weaker stems and reduced blooming. For indoor cultivation, a south-facing window or supplemental grow lights provide the necessary intensity.
Watering Schedule
Watering should be approached with caution, as Pachypodium horombense is susceptible to rot from overwatering. During its active growing season, typically late spring through summer, water thoroughly only when the soil has completely dried out. A “soak and dry” method is recommended. During its winter dormancy, watering should be significantly reduced or ceased entirely.
Soil and Potting
A well-draining, gritty potting mix is crucial for the Rhino Plant to prevent root rot. A suitable mix consists of a cactus or succulent blend with additional perlite or pumice. Good drainage is paramount, as the caudex stores water, making it vulnerable to excess moisture.
Temperature and Humidity
Pachypodium horombense is adapted to warm climates and prefers temperatures between 25-32°C (75-90°F) during its active growth. It is sensitive to cold. During winter dormancy, it should be kept completely dry, ideally around 10°C (50°F), and protected from frost. High humidity is not required; good airflow is beneficial.
Fertilizing
During the active growing season, from spring to late summer, Pachypodium horombense benefits from occasional fertilization. A balanced, low-nitrogen fertilizer diluted to half strength can be applied every 2-3 weeks. Limiting fertilizer use is recommended.
Repotting Your Rhino Plant
Repotting Pachypodium horombense is necessary when the plant becomes root-bound or the soil mix has degraded. The best time for repotting is at the beginning of the growing season, in late spring or early summer. When selecting a pot, opt for one that is not excessively large. Terracotta pots are preferred for their breathability and drainage.
When repotting, carefully remove the plant from its old container. Inspect the roots for any signs of rot or damage, trimming away unhealthy portions. Due to the plant’s spines, wrapping the caudex in several layers of newspaper can make handling easier and safer. Place the plant in its new pot with fresh, well-draining succulent mix. After repotting, delay watering for a week or two to allow any root wounds to heal.
Propagating Rhino Plants
Propagating Pachypodium horombense is primarily achieved through seeds, which offer a high success rate. Before sowing, soak the seeds in warm water for 24 hours. Sow the seeds about 5 mm deep in a sterile, moist, sandy medium. Maintaining a consistent temperature of 27-35°C (80-95°F) will facilitate sprouting, which can begin within 3-4 days.
While propagation from cuttings is possible, it is generally less successful. If attempting cuttings, allow them to dry and callus for 5 to 8 days after removal from the parent plant before potting them into a suitable medium.
Troubleshooting Common Rhino Plant Issues
One of the most frequent problems encountered with Pachypodium horombense is root rot, almost always a result of overwatering. Symptoms include a soft, mushy caudex and yellowing or dropping leaves. To address this, unpot the plant, trim away any rotted roots, allow the plant to dry and callus for several days, and then repot into fresh, dry, well-draining soil.
Pests such as mealybugs and spider mites can occasionally affect the Rhino Plant. Regularly inspecting the plant, especially in the crevices of the caudex and undersides of leaves, can help detect infestations early. Treatment often involves wiping away pests with an alcohol-soaked cotton swab or applying an insecticidal soap. Environmental stress can also cause issues; for instance, sudden temperature changes or insufficient light may lead to leaf drop.
Rhino Plant Toxicity
Pachypodium horombense, like other members of the Pachypodium genus, has toxic sap. Ingestion could cause irritation or more severe symptoms. The plant also features sharp spines, which can cause physical injury upon handling. It is advisable to handle the plant with caution, using gloves, and to keep it out of reach of children and pets.