Habitat and Ecology
​Rhododendron gracilentum is a delightful, very dwarf epiphytic or terrestrial shrub belonging to the Vireya section of Rhododendron. It is native and endemic to Papua New Guinea, found growing in montane mossy forests and shrubland at high elevations, typically between 2,000 and 2,800 metres. This species thrives in a cool, wet, and misty environment that provides constant atmospheric moisture, growing on moss-covered branches or steep, exposed slopes. It is a slow-growing, compact plant well-adapted to the cool, high-altitude tropics.
​Description
​This is an evergreen perennial shrub that remains tiny and highly branched, usually growing to less than 50 cm in height, forming a naturally bushy and spreading mound. The leaves are small (0.8-1.5 cm long), narrowly elliptical, and thickly leathery, with a glossy green upper surface. The lower surface is finely coated with small, dark brown, disc-shaped scales (lepidote). The flowers are showy for the size of the plant, mostly produced solitarily (rarely in pairs) and pendent (hanging vertically) from the branch tips. The corolla is cylindrical to narrowly funnel-shaped, 2-3 cm long, and typically a beautiful red or deep pink colour, often covering the plant completely in spring.
​Cultivation
​Rhododendron gracilentum is a demanding cool-intermediate growing plant that is not frost hardy (RHS Hardiness Rating H2). It must be grown under glass in a cool conservatory, sunroom, or greenhouse in the UK. It requires bright, filtered light and should be shielded from intense, direct sun. The substrate must be acidic (pH 4.5-6.0) and extremely open/porous; use an ericaceous compost mix heavily amended with orchid bark, perlite, and/or sphagnum moss (synthetic peat is suitable). The shallow roots must be kept moist at all times; this plant does not tolerate drying out.
​Optimal Daytime Temperature: 15-20 C (59-68 F)
​Optimal Nighttime Temperature: Cool nights are essential, ideally 10-15 C (50-55 F); temperatures below 5 C should be avoided.
​High humidity (60%+) is essential, along with good air circulation. Feed monthly during the active growing season with a balanced, dilute ericaceous liquid fertiliser.
​Unique Features
​This miniature Vireya Rhododendron is a highly desirable collector's species, renowned for its prolific spring bloom when the entire plant covers itself in large, pendent, deep red/pink flowers. Its tiny, glossy leaves and compact, naturally mounding habit make it perfect for growing in containers or hanging baskets, where its elegant, vertically-hanging flowers can be easily appreciated. It is an ideal plant for showcasing the diversity of tropical mountain flora.
​Specifications
​Plant Size: propagations produced in the UK about 12 cm tall
​Plant Family: Ericaceae
​Plant Passport: A Rhododendron gracilentum B 140084 C [user input] D GB