Schlumbergera (Zygocactus) 'Thor Olga'

Schlumbergera 'Thor Olga' is a cultivated hybrid in the Cactaceae family, more widely known as a Zygocactus or Christmas Cactus. Its parent species originate from the coastal mountain forests of south-eastern Brazil, where they grow as epiphytes or lithophytes in humid, shaded conditions. In their native range, these plants root in tree branches or rocky crevices, receiving dappled light, high humidity, and free-draining organic debris as their growing medium.

The stems are composed of flattened, jointed segments (phylloclades) with slight notching along the edges. 'Thor Olga' produces large, tubular flowers in shades of white flushed with soft pink, sometimes deepening in colour towards the petal edges depending on light and temperature. The blooms appear at the tips of mature segments and are adapted for pollination by hummingbirds in their natural environment.

This hybrid grows in an arching to cascading form and can become a substantial, floriferous specimen over time. Flowering is stimulated by shorter day lengths and cooler night temperatures, making it a reliable bloomer when seasonal cues are provided.

Care Tips:

• Light: Bright, indirect light is best. Some morning or late afternoon sun can enhance growth and flowering, but avoid intense midday rays to prevent stem scorch.
• Water: Maintain even moisture in the potting mix during active growth and flowering. After blooming, allow the top layer of soil to dry before watering again.
• Humidity: Prefers moderate to high humidity. Use a pebble tray with water or occasional misting during dry indoor conditions.
• Media: A free-draining, slightly acidic mix containing orchid bark, peat, and perlite will mimic its natural epiphytic growing conditions.
• Fertiliser: Feed monthly during growth with a balanced liquid fertiliser at half strength. Use a high-potassium fertiliser in the weeks leading up to flowering to promote bud development.
• Temperature: Best grown at 18–24°C during the growing season. To set buds, provide 12–15°C nights for several weeks in autumn.
• Repotting: Repot every 3–4 years after flowering, refreshing the mix and using a slightly larger pot if required.
• Propagation: Take cuttings of 2–3 joined segments in spring or early summer, allow them to callus for 24 hours, and plant in a well-draining mix.