Notocactus ottonis, known as the Lemon Ball Cactus, is a popular houseplant. This South American native thrives indoors with proper care. Its spherical shape and vibrant blooms make it a favored choice for plant enthusiasts.
Notocactus Ottonis Distinctive Characteristics
Appearance and Size
Notocactus ottonis is typically spherical to slightly flattened. The cactus body is often glossy green or bluish-green, sometimes turning purple with stress or increased sun. This compact plant usually reaches up to 4 inches (10 cm) tall and 6 inches (15 cm) wide.
Its surface has 6 to 12 well-defined ribs. Along these ribs, areoles bear slender, hair-like spines. These short spines are light brown to reddish and can be straight, curved, or twisted. They are generally soft to the touch.
Unique Flowering
The plant produces showy, wide, yellow flowers from its apex. These bright blooms can have slight reddish stripes or be shades of orange, peach, salmon, or pink-red. These vibrant flowers appear in spring or early summer.
Blooms can reach up to 2.4 inches (6 cm) in diameter, creating a striking contrast against the green body. The plant often flowers at a young age.
Comprehensive Care Guide
Light Requirements
Notocactus ottonis thrives in bright, indirect light or filtered sun. Place the cactus in a sunny spot receiving at least 6 hours of direct sun daily. Protect the plant from harsh, direct afternoon sun, especially in warmer climates, to prevent scorching.
Insufficient light causes etiolation, resulting in a stretched appearance. In winter, when sunlight intensity decreases, the cactus prefers full sun.
Watering Practices
Proper watering is important for Notocactus ottonis, which prefers a “soak and dry” method. During its active growing season (spring and summer), water regularly, typically every week or two. Allow the soil to dry completely between waterings to prevent root rot.
In cooler winter months, during dormancy, reduce or stop watering entirely. Keeping the plant dry during dormancy prevents rot, as roots are sensitive to cold and wet conditions. Good drainage is essential, as this cactus is susceptible to root rot in soggy soil.
Soil and Potting
The ideal soil mix for Notocactus ottonis is well-draining, gritty, and aerated. A specialized succulent or cactus mix is suitable, often enhanced with sand, perlite, pumice, or small gravel to improve drainage. This prevents waterlogging, which harms the plant’s root system.
Pots with drainage holes are necessary for excess water to escape. Repot every two to three years, or when the plant becomes root-bound, to refresh the soil and provide new nutrients. Repot during the early growing season, ensuring the soil is dry before gently removing the plant and backfilling.
Temperature and Humidity
Notocactus ottonis grows best in warm conditions during its active period, with optimal temperatures from 65-80°F (18-27°C). During winter dormancy, the plant needs cooler, dry conditions, ideally 40-59°F (4-15°C).
While it tolerates temperatures down to about 39°F (4°C), avoid prolonged cold and wet conditions to prevent rot. This cactus prefers dry air and does not tolerate high humidity, which can cause fungal issues. Maintain good air circulation around the plant.
Fertilization
Fertilize Notocactus ottonis during its active growing season (spring and summer). A low-nitrogen, high-potassium fertilizer, diluted to half strength, supports healthy growth and flowering. Fertilizing once or twice during this period is sufficient.
Avoid fertilizing during dormancy (late fall and winter). Too much fertilizer, or fertilizing outside the growing season, can lead to elongated growth or root damage. Replacing potting soil every year or two can also provide sufficient nutrients.
Propagation Methods
Notocactus ottonis can be propagated through offsets (pups) and seeds. Offsets are the most common and quickest method. The plant produces these smaller clones around its base as it matures.
To propagate using offsets, carefully remove them from the parent plant, ideally when at least 2 inches in diameter. Allow the cut surface to dry and form a callus for a few days to a week before planting. Once callused, plant the offset in a well-draining cactus mix, and water sparingly until roots develop.
Seed propagation is feasible but slower. Seeds can be sown in a sandy loam soil mixture and kept in warm, humid conditions for germination. This method requires patience, as seedlings develop slowly.
Addressing Common Issues
Common issues affecting Notocactus ottonis stem from improper care. Root rot is a frequent problem, indicated by a mushy or discolored base, caused by overwatering or poor drainage. If suspected, cease watering, remove the plant, and allow roots to dry before repotting in fresh, well-draining soil.
Etiolation, a stretched or elongated stem, occurs due to insufficient light. Resolve this by gradually moving the plant to a brighter location. Sunburn or scorching appears as brown or yellow patches from too much direct sun. Prevent this by providing filtered light or partial shade during the hottest parts of the day.
Pests like mealybugs and spider mites can affect the plant. Mealybugs appear as small, white, cottony masses; spider mites are indicated by fine webbing. Treat these pests with insecticidal soap or neem oil. For persistent infestations, a specialized pest control spray may be necessary.