Plants with unpleasant odors are informally known as “poo plants” due to their smell resembling decaying organic matter. Despite their off-putting scent, these botanical curiosities often feature intricate and beautiful blooms.
Unveiling the “Poo Plant”
The term “poo plant” refers to succulent species like Stapelia, Huernia, and Orbea, commonly called “carrion flowers.” These plants are native to arid and semi-arid Southern and Eastern Africa. They have fleshy, four-sided, often toothed stems that resemble cacti, though they are succulents.
Their flowers are diverse in shape, color, and size. For instance, Stapelia gigantea produces massive, star-shaped flowers over 10 inches across, with cream-colored petals striped with red. Huernia species often display five-lobed, bell-shaped flowers, frequently patterned with vivid stripes or spots. This unique appearance often contrasts sharply with their emitted odor.
The Science Behind the Stench
The foul odor emitted by carrion flowers is an evolutionary strategy called carrion mimicry. They produce scents imitating decaying flesh or feces to attract flies. Flies, like blow flies and flesh flies, are drawn to the scent, mistaking flowers for feeding or egg-laying sites.
Mimicry is achieved through chemical compounds. Common compounds include diamines (putrescine, cadaverine) and sulfur compounds (dimethyl disulfide, dimethyl trisulfide). These compounds are potent enough to lure flies, even in low concentrations. Flies inadvertently pick up and transfer pollen, facilitating reproduction.
Caring for Your Carrion Flower
Successful cultivation requires understanding their needs, which mirror their native arid environments. They are low-maintenance succulents when basic requirements are met, ensuring healthy growth and unique flowering.
Light Requirements
Carrion flowers thrive in bright, indirect sun or partial shade, especially during hot periods. Full sun is tolerated by some species, but intense midday exposure can cause sunburn or stem discoloration, indicating stress. Indoors, an east or west-facing window provides adequate light, offering morning or afternoon sun without harsh direct light. Insufficient light may result in weak growth and reduced flowering.
Watering Practices
Highly drought-tolerant, these succulents store water in their thick stems. Overwatering is the most common mistake, quickly leading to root rot. Allow soil to dry completely between waterings during the active growing season (spring and summer). Reduce or stop watering entirely during dormant winter months, as plants require little moisture. Wrinkled stems can indicate a need for water, but underwatering is safer.
Soil and Potting
Well-draining soil is crucial to prevent waterlogging and root rot. A specialized succulent or cactus potting mix is ideal, often amended with gritty materials like perlite, pumice, coarse sand, or gravel to enhance drainage. A common recommendation is a mix comprising equal parts potting soil, perlite, and coarse sand. Shallow pots with drainage holes are preferable due to their short root systems and benefit from quick soil drying. Terra-cotta pots are also beneficial due to their porous nature, promoting faster moisture evaporation.
Temperature and Humidity
Carrion flowers prefer warm temperatures, ideally 70-90°F (21-32°C) during their active growing season. They are not frost-tolerant and need protection below 50°F (10°C). In cooler climates, move outdoor plants indoors before cold weather. Adapted to arid environments, they tolerate low humidity well, suiting typical indoor conditions. Good air circulation is also beneficial to prevent fungal issues.
Fertilization
Heavy fertilization is not required. During the growing season (spring to summer), apply a balanced, water-soluble fertilizer diluted to half or quarter strength monthly or every few weeks. Some growers opt for a low-nitrogen, high-phosphorus fertilizer to encourage blooming. Sparingly fertilizing established plants is sufficient; excessive nutrients can lead to lush stem growth at the expense of flowers. Cease fertilization entirely during dormant winter.
Managing the Odor
While integral to their biology, the distinctive scent can concern growers. The odor is typically strong only when in bloom, lasting about a week per flower. It is usually not overwhelming unless one is close to the blooming plant.
Strategic placement can mitigate the smell’s impact. Growing them outdoors during flowering, on a patio or balcony, allows natural ventilation. Indoors, good air circulation from a well-ventilated room or open window helps dissipate the odor. Some growers snip off indoor flowers if the aroma becomes problematic. Understanding the smell is temporary and linked to their unique pollination strategy helps manage expectations.