Grammatophyllum scriptum, known as the “Leopard Orchid” or “Tiger Orchid” for its distinct markings, is a large orchid species celebrated for its abundant blooms. Native to Borneo, the Philippines, New Guinea, and the Southwest Pacific islands, it thrives in warm, bright coastal environments, often growing on tree trunks and branches.
Essential Care Requirements
Correct light is foundational for Grammatophyllum scriptum health and blooming. These orchids require bright, indirect light, ideally receiving 60-80% of full sunlight. An east-facing window providing morning sun is excellent. A south-facing window can also work if shaded with a sheer curtain to prevent leaf scorch from intense midday light. Healthy leaves should be lime-green with a slight yellowish tint.
Watering Grammatophyllum scriptum involves understanding its needs as a large, thirsty orchid. During their active growing season (March to October) and when flower spikes emerge, water frequently and heavily. Ensure roots become thoroughly wet but dry out quickly. Allow the potting medium to approach dryness before rewatering. Watering frequency depends on pot size, medium, temperature, and air circulation.
Reduce watering slightly during cooler, less active months, but pseudobulbs should remain plump; if they shrivel, increase watering. Water low in alkalinity, like rainwater or distilled water, minimizes mineral buildup. Tap water can be used, but may require more frequent repotting.
Appropriate temperature and humidity are crucial for these tropical orchids. Grammatophyllum scriptum thrives with daytime temperatures between 72-85°F (22-30°C). A night temperature drop of about 10°F (6°C), ideally to 65-75°F (18-24°C), helps initiate flower buds. High humidity, 45-70%, is beneficial and can be achieved with humidity trays, humidifiers, or by grouping plants. In high humidity, excellent air circulation prevents fungal and bacterial issues.
Consistent fertilizing supports Grammatophyllum scriptum growth. During the active growing season, when new growths emerge, fertilize regularly. Apply a balanced NPK fertilizer (e.g., 20-20-20 or 15-15-15) at half strength with almost every watering for bark mixes. Flush the pot with clear water monthly to prevent fertilizer salt buildup, as roots are sensitive to it. During less active periods, such as late fall through winter, a lighter feeding once every other week or reduced feeding is sufficient.
Potting and Repotting
Potting and repotting are important for the large root system of Grammatophyllum scriptum. These orchids benefit from a coarse, well-draining epiphyte mixture, such as a medium to large grade orchid bark mix, sphagnum moss, or charcoal. Large specimens thrive in sturdy pots or wire/wooden baskets, which accommodate their extensive root systems and provide excellent airflow.
Repotting is recommended every 1-2 years, ideally in the spring when new growth begins or after flowering. This is necessary when the potting medium breaks down or the plant outgrows its container. To repot, carefully remove the plant from its old pot.
Trim dead roots or pseudobulbs, then position the plant with its oldest pseudobulbs towards the edge of the new pot. Fill the pot with fresh medium, pressing firmly to stabilize the plant. Choose a pot large enough for 1-2 years of new growth to minimize disturbance.
Encouraging Blooms
To encourage Grammatophyllum scriptum to bloom, provide specific environmental cues. Sufficient light intensity is paramount for flowering. A distinct day-to-night temperature differential helps trigger flower initiation.
The plant needs to reach maturity, with enough pseudobulbs, to consistently produce flower spikes. Some growers find a short, pronounced dry period (1-2 weeks of reduced irrigation) can encourage blooming. Following this, a switch to a high-phosphorus fertilizer for several weeks can further stimulate flower production. Grammatophyllum scriptum produces long, often 2-3 foot tall, flower spikes with numerous waxy flowers that can last 1-2 months.
Common Problems and Solutions
Yellowing leaves can signal overwatering, underwatering, or nutrient deficiency. Dark green leaves with no blooms often indicate insufficient light. Shriveled pseudobulbs typically point to underwatering; increasing watering frequency can resolve this.
A lack of blooms, despite healthy growth, is frequently due to insufficient light or plant immaturity. Adjusting the plant’s location to receive brighter, indirect light and ensuring a proper day-night temperature differential can encourage flowering. Pests like mealybugs, scale, and spider mites can affect Grammatophyllum scriptum. Inspect regularly and treat promptly with horticultural oils or insecticidal soaps to prevent severe infestations. Fungal or bacterial infections appear as water-soaked, browning, or black spots on leaves. Manage by removing infected tissue with sterile tools and improving air circulation. Ensuring leaves dry before nightfall can also prevent bacterial growth.