Hoya callistophylla, also known as stiff-leaved hoya and callistophylla wax plant, is an evergreen climbing succulent plant. Hoya callistophylla is native to Asia, specifically Malaysia, Thailand, and Borneo. The plant is noted for its gorgeous leaves with contrasting light colors and dark veins. Hoya callistophylla is a popular indoor ornamental plant due to its disease resistance. This plant can grow up to 150 cm; its petioles are usually curved and 1 to 3 cm long. The leaves are thick and elliptical to lanceolate, up to 25 cm long and 9 cm wide. Hoya callistophylla flowers are spectacular, with bright colors that change depending on the season and conditions, are fragrant, and last up to 7 days.
Hoya Callistophylla Plant Care
Soil
Hoya callistophylla grows best in well-drained and aerated soil. Avoid stagnant water at the roots, and make sure the soil holds enough water to maintain moisture. The ideal pH of the soil is 6.3 to 7.5 (slightly acidic to neutral). Use a mixture of peat moss and perlite or burnt husk and cocopeat for a rich, nutritious soil medium that ensures aeration and prevents waterlogging.
Watering
Hoya callistophylla does not require daily watering due to its succulent nature; however, too little water can also cause the plant to dry out and die. The watering process should be balanced to grow a healthy plant. The soak-and-dry method works. Water the plant thoroughly before drying the soil for a few days. Water again once the top layer of soil is slightly dry. Lack of water can cause leaves to turn yellow and loose structure, while over-watering can increase the risk of infection.
Lighting
Hoya callistophylla grows well in bright, dappled sunlight, but avoids direct sunlight during the dry season. Brighter light can enhance the color of the leaves, but avoid direct sunlight that can burn the leaves. Place near eastern windows or behind light curtains, or use 20%–40% shade or artificial grow lights.
Remperature
Hoya callistophylla is quite resistant to extreme temperatures and favors moderate temperatures. The ideal temperature for this plant is 18–27 °C for best growth; the lowest temperature it can withstand is around 10 °C; below that, the plant will wilt. Maintaining the ideal temperature for Hoya callistophylla is easy in temperate climates; bring the plant indoors if the weather is very cold. The plant should be placed near heaters, but not close to them. The right temperature prevents delayed flowering and other growth problems.
Humidity
Hoya callistophylla loves moisture, which helps maintain the shape and color of its leaves. The ideal humidity is 50%–70%, which is generally present in most homes. Too much humidity can lead to fungal and bacterial infections.
Fertilizer
Hoya Callistophylla does not require a lot of nutrients, but it does well with a high nitrogen-containing fertilizer twice a week or a slow-release fertilizer once a month. Fertilizers containing nitrogen and phosphorus are excellent for flower growth. Place the fertilizer about 2 cm from the stem to avoid poisoning, and do not apply too much. Apply fertilizer to moist soil to increase absorption and reduce the risk of toxicity.
Pruning
Pruning Hoya callistophylla can be done to improve appearance or to allow the vines to grow larger. Use clean pruning shears without damaging healthy foliage or flowers. Also, use pruning to check for and remove dark patches or abnormal growth that could spread and damage the plant.
Propagation
Stem Cutting Method:
1. Sterilize and clean all equipment to prevent infection.
2. Select a non-flowering stem of Hoya callistophylla and cut it with two or more nodes at the end.
3. Fill the container with the growing medium mixture and cover it with plastic to retain moisture.
4. Plant the cuttings in the growing media mix, and if desired, add growth hormones.
5. Ensure the temperature is around 21 degrees Celsius. Water the plants and apply fertilizer.
For the first 14 days, keep the hoya well watered and fertilized, and protect the plant from infections. Shoots will appear between three and six weeks. The plant is ready to be transplanted to a larger pot and cared for like an adult plant after 2–3 months.
Writer : Novilla Fitra Najwa Suryadi (College Student Of Bandung Islamic State University, Indonesia)