Paphiopedilum callosum (Callus Paphiopedilum) is an evergreen, tender orchid boasting striking burgundy flowers, 3-4 across (8-10 cm), with white sepals and petals adorned with purple and green stripes. The petals curl downward and have hairy, black, raised spots along the top edge. Blooming in the spring and early summer, the flowers are borne usually singly (occasionally 2) on upright purple stems. The attractive foliage of dark green mottled leaves, up to 12 in. long (30 cm), is narrowly elliptic. Native to Vietnam, Thailand, southern Laos, Malaysia, and Cambodia, Paphiopedilum callosum grows in evergreen, seasonal, broad-leaved forests and sheltered mossy places in the rock cracks at altitudes of 980-6500 ft. (300-2000 m). Paphiopedilum callosum is an easy orchid to grow.

• Grows up to 8-16 in. tall (20-40 cm).
• Grows in an open medium in a shaded position in summer protected from direct sunlight but move to a bright, unshaded position in winter. An east or west window, or near a shaded south window is best.
• Needs a night temperature of 61-71°F (16-22°C) and a daytime temperature of 68-77°F (20-25°C).
• Maintain high humidity (50-70%) for most of the year by standing the container in a tray of damp pebbles - do not mist.
• Water frequently in spring and summer. The substrate between waterings should dry well, but not dry completely. 
• Paphiopedilum callosum needs a dormant period to stimulate flowering. During dormancy, night temperature should not exceed 59°F (15°C) and watering should be replaced with a light, clear spraying of the substrate.
• Feed once every two weeks in the spring and summer, once every 4 weeks in the fall and winter.
• When the blooms are finished, cut the spike down to the level of the leaves. Continue watering and fertilizing and within a year a new growth will spike to begin the blooming cycle again.
• When the plant has finished blooming is a good time to repot your orchid. Repot every year. Paphiopedilum orchids like to be tight in their pots. An average plant should have a 4-6 in. pot (10-15 cm).
• Large plants can be divided by pulling or cutting the fans of the leaves apart, into clumps of three to five growths.
• Generally disease free. Keep an eye out for aphids, glasshouse red spider mites, and mealybugs.
• Native to Vietnam, Thailand, southern Laos, Malaysia, and Cambodia.

Tips for reblooming

• Check regularly if the plant is secure in its pot and the root system is sound. If not, repot.
• Try applying a blooming fertilizer in the early spring months.
• Move the orchid to a cooler, brighter location for a week, then return it to its original location.