Rocktrumpet

Mandevilla sanderi is native to the state of Rio de Janeiro in southeastern Brazil, where it grows as a scrambling vine in the Atlantic Forest (Mata Atlantica) — one of the world's most biodiverse and threatened ecosystems.

• Named in honor of Henry Frederick Conrad Sander (1847–1920), a prominent German-born British nurseryman known as the "Orchid King" for his vast orchid import business
• The genus Mandevilla is named after Henry John Mandeville, a British diplomat who served in Argentina and introduced the genus to Western horticulture in the 1840s
• The species was formerly classified as Dipladenia sanderi, and the name "Dipladenia" is still widely used in the horticultural trade for compact cultivars
• Became commercially important in the late 20th century as breeders developed compact, freely blooming varieties suitable for container gardening
• The modern Mandevilla market is dominated by interspecific hybrids that combine the large flowers of M. sanderi with improved heat tolerance and disease resistance from other species
• Today, Mandevilla is one of the top-selling flowering container plants worldwide, with millions sold annually
• The genus Mandevilla contains approximately 200 species of tropical American vines and shrubs
• Brazil's Atlantic Forest, the native habitat of this species, has been reduced to less than 12% of its original extent

Rocktrumpet is a moderately vigorous evergreen twining vine with glossy foliage, typically growing 1–3 m long in cultivation, though it can reach 4–5 m in ideal tropical conditions.

Stems: Slender, green, twining around supports, producing a milky white sap when cut (characteristic of Apocynaceae). Young stems are green and slightly pubescent.

Leaves: Elliptic to ovate, 5–12 cm long and 2.5–5 cm wide, dark glossy green, thick and leathery, with smooth margins. Leaves are arranged oppositely along the stems and have a distinct, slightly puckered texture.

Flowers: Large and showy — trumpet-shaped (funnelfiform), 7–10 cm across, with 5 broad, overlapping, rose-pink petals that flare broadly from a narrow tube. The throat is often deeper pink to red. Flowers are produced in loose terminal cymes of 3–7 blooms, continuously from early summer through fall. Each flower lasts several days.

Fruit: Paired, narrow follicles, rarely produced in cultivation.

Roots: Fibrous root system. Performs best when slightly root-bound in containers, which promotes flowering.

Rocktrumpet grows naturally as a scrambling vine in the tropical Atlantic Forest of southeastern Brazil, where it climbs through the understory and along forest edges in warm, humid conditions.

• Requires warm temperatures (18–30°C) — does not tolerate cold or frost
• Thrives in full sun to partial shade — best flowering in at least 6 hours of direct sun
• Prefers moist, well-drained, fertile soils rich in organic matter
• The milky sap is characteristic of the Apocynaceae family and may irritate skin
• Flowers are pollinated by hummingbirds and large bees in its native Brazil
• In cultivation, it is valued for exceptionally long bloom duration — plants can flower continuously for 4–5 months
• Modern hybrids are bred for compact habit, disease resistance, and flower production
• Susceptible to mealybugs, spider mites, and whitefly, especially when grown indoors or in greenhouses
• Not invasive in most regions as it cannot survive winter outside tropical and subtropical zones

Rocktrumpet is primarily grown as a container or patio plant in most regions, brought indoors for winter.

Light: Full sun — at least 6 hours of direct sun daily for best flowering. Tolerates light shade but blooms less.

Soil: Well-draining, fertile potting mix. A blend of peat, perlite, and compost works well. pH 5.5–6.5.

Container: Use a pot only slightly larger than the root ball — Rocktrumpet blooms best when slightly root-bound. Ensure excellent drainage.

Watering: Water thoroughly when the top 2–3 cm of soil feels dry. Do not allow to sit in water. Reduce watering in winter when growth slows.

Fertilization: Feed every 2 weeks during the growing season with a bloom-boosting fertilizer (higher phosphorus). This is essential for continuous flowering.

Temperature: Warm conditions (18–30°C). Bring indoors when temperatures fall below 10°C. Does not tolerate frost.

Pruning: Pinch growing tips to encourage bushier growth. Prune back by up to one-third in early spring to refresh the plant and promote new flowering wood.

Support: Provide a small trellis, obelisk, or stakes in the container for the twining stems.

Winter Care: Overwinter indoors in a bright, cool (13–16°C) location. Reduce watering and stop fertilizing. Move back outdoors after all frost danger has passed.

Hardiness: USDA Zones 10–11. Grow as an annual or houseplant elsewhere.

Propagation: By semi-hardwood cuttings in summer. Root in moist potting mix with bottom heat.