Hoya merrillii is a captivating Hoya species, appreciated for its attractive foliage and fragrant flowers. Native to the Philippines, particularly Mindoro Island, its relatively straightforward care makes it an appealing choice for new cultivators. As an epiphyte, it naturally grows on other plants, absorbing moisture and nutrients from the air rather than relying on soil.
Understanding Hoya Merrillii
Hoya merrillii has unique physical characteristics. Its leaves are typically thick, glossy, and can be heart-shaped or lance-shaped. These dark green leaves often feature prominent veins. When exposed to bright, indirect light, the foliage develops striking sun-stress coloring, turning rich shades of red or purple.
Its captivating blooms are star-shaped, typically pale yellow to cream, sometimes with pink hues. They are often sweetly scented and last for several days. Hoya merrillii is a heavy bloomer in warmer months, often reblooming from the same flower stalks.
Hoya Merrillii Care Guide
Light Requirements
Hoya merrillii thrives in bright, indirect light, mimicking its natural filtered light environment. An east-facing window or bright, diffused light is ideal. Brief exposure to morning sun can enhance reddish hues, but intense afternoon sun should be avoided to prevent leaf burn or bleaching. Insufficient light may result in leggy growth and fewer blooms.
Watering Practices
Hoya merrillii is sensitive to overwatering. Allow the top few inches of soil to dry completely between waterings. Thoroughly soak the soil until water drains from the bottom of the pot. Water less frequently in fall and winter. Yellowing or mushy leaves signal overwatering, while wilting or crispy edges indicate underwatering.
Soil and Potting
As an epiphyte, Hoya merrillii requires a well-draining, airy, chunky soil mix. Components like orchid bark, perlite, coco husk, or coco coir replicate its natural growing conditions. A good mix includes two parts orchid bark, one part coco coir, and one part perlite. It prefers to be slightly root-bound, so frequent repotting is unnecessary. Repot only in spring when the plant has outgrown its container.
Temperature and Humidity
Hoya merrillii prefers warm, humid environments. Optimal temperatures are 65-85°F (18-29°C); protect from temperatures below 50°F (10°C) and cold drafts. High humidity (60-80%) benefits growth. While it tolerates lower humidity, it thrives with increased moisture. Achieve this by misting, using a pebble tray, or a room humidifier.
Fertilization
Hoya merrillii is not a heavy feeder but benefits from regular fertilization during its active growing season. Apply a balanced liquid fertilizer or one high in potassium during spring and summer. Dilute fertilizer to half strength to avoid over-fertilization. Fertilize every two weeks or monthly to support healthy growth and blooming. Some growers continue to fertilize at reduced strength during cooler months.
Propagating Hoya Merrillii
Propagating Hoya merrillii is commonly done through stem cuttings, which is a popular and effective method. Take cuttings when the plant is actively growing. Select a healthy stem section with at least two nodes and a few leaves. Remove leaves from the bottom node to expose it.
Root cuttings in water, where roots will typically emerge within a few weeks. Alternatively, plant cuttings directly into a well-draining, airy potting mix. Keep the rooting medium consistently moist, but not waterlogged, to encourage root development. Once rooted, care for it as a young plant.
Common Hoya Merrillii Issues
Hoya merrillii can encounter common problems, often related to environmental factors or pests. Overwatering leads to yellowing leaves, mushy stems, and root rot. Underwatering causes leaves to wilt, droop, or develop crispy brown edges, leading to leaf drop. Allowing soil to dry adequately between waterings prevents these issues.
Insufficient light results in leggy growth and fewer blooms. Too much direct sunlight can bleach or burn leaves. Adjusting placement to bright, indirect light is the solution.
Pests like mealybugs, spider mites, aphids, and scale insects cause sticky residue (honeydew), yellowing leaves, or stunted growth. Manage these with horticultural oil, neem oil, or insecticidal soap. Fungal problems like root rot or gray mold arise from consistently wet conditions or poor air circulation. Improving drainage and airflow mitigates these concerns.