Hoya kerrii is arguably one of the most recognizable and beloved Hoya species, primarily famous for its distinctive heart-shaped leaves, earning it common names like "Sweetheart Hoya," "Heart Leaf Hoya," or "Valentine Hoya."
Origin and Discovery
Hoya kerrii is native to Southeast Asia, with its natural range including South China, Vietnam, Laos, Cambodia, Thailand, and the Indonesian island of Java. It typically grows as an epiphyte in the humid, warm environments of tropical and subtropical forests, often climbing on trees.
The species was discovered and collected by Arthur Francis George Kerr, an Irish (or British, sources vary) physician and botanist, in 1910 or 1911 in the Doi Suthep mountains west of Chiang Mai, Northern Thailand, at an altitude of approximately 390 meters above sea level. A specimen was then transplanted to Kew Gardens, where it flowered in August 1911.
The species was formally described by William Grant Craib in 1911.
The original publication details are:
Craib, W. G. (1911). Contributions to the Flora of Siam (continued). Bulletin of Miscellaneous Information, Kew, Vol. 1911, pp. 418-419.
Key Characteristics
Leaves: The most defining characteristic of Hoya kerrii is its thick, fleshy, heart-shaped leaves. These leaves are typically dark green, but variegated forms
Growth Habit: It is a climbing plant that can grow quite large in its natural habitat, reaching up to 4 meters high. Indoors, it can be grown as a vining plant on a trellis or in a hanging basket. However, it's notorious for its slow growth rate, especially from single-leaf cuttings.
‘’Zombie Hearts’’ Single Leaf Cuttings: Hoya kerrii is famously sold as a single, rooted heart-shaped leaf, particularly around Valentine's Day. While these single leaves can survive for many months or even years, they often do not develop into full vining plants unless a portion of the stem with a node is included in the cutting. They are largely novelty items, beautiful but rarely growing beyond the single leaf. That will not say it is impossible.
Flowers: When mature and given proper care, Hoya kerrii produces clusters (umbels) of small, waxy, star-shaped flowers, typically around 5 cm in diameter with up to 25 flowers per umbel. The flowers are usually white to pale pink or cream, often with a contrasting reddish-brown or purplish-brown corona (the center of the flower). They produce small balls of nectar and often have a subtle, sweet, sometimes described as a faint honey or vanilla-like, fragrance, particularly noticeable at night. Flowers can last for several weeks.
Care Requirements for Indoor Cultivation
Light: Prefers bright, indirect light. A spot near an east or west-facing window is ideal. While it tolerates lower light, it will grow slower and be less likely to flower. Avoid harsh, direct afternoon sun, which can scorch its thick leaves.
Watering: Like succulents, Hoya kerrii stores water in its thick leaves. It's crucial to allow the soil to dry out completely between waterings to prevent root rot, which is a common issue. Reduce watering significantly in winter.
Humidity: Average household humidity is usually sufficient. However, it appreciates moderate to high humidity (around 50-60% or higher), especially for optimal growth and flowering.
Temperature: Thrives in warm temperatures, ideally between 18−27∘C. It is not cold-hardy and should be protected from temperatures below 10∘C.
Soil: Requires a very well-draining, airy, and chunky potting mix.
Potting: Hoya kerrii prefers to be somewhat root-bound. Repot only when necessary, typically every few years, and only move up one pot size to avoid excess moisture around the roots.
