Golden trumpet (allamanda) Allamanda cathartica
Golden trumpet (allamanda) (Allamanda cathartica) is an evergreen perennial shrub in the Apocynaceae family, native to Brazil and the Guianas. It grows 2–6 m (6.6–20 ft) tall and 2–4 m (6.6–13 ft) wide, wants full sun and moderate water, and is hardy to about 2 °C (36 °F). Space plants about 2 m (6.6 ft) apart.
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Golden trumpet (allamanda) at a glance
| Type | Perennial shrub, evergreen |
|---|---|
| Family | Apocynaceae |
| Mature height | 2–6 m (6.6–20 ft) |
| Mature spread | 2–4 m (6.6–13 ft) |
| Spacing | 2 m (6.6 ft) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance none |
| Soil pH | 5.5–7 |
| Cold hardiness | About 2 °C (36 °F) once established (roughly USDA zone 10) |
| Heat stress | Likely above about 38 °C (100 °F) |
| Flowering | from about April for 21–39 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Brazil and the Guianas |
| Common in gardens of | 🇧🇷 Brazil, 🇹🇭 Thailand, 🇸🇬 Singapore, 🇲🇾 Malaysia, 🇵🇭 Philippines, 🇮🇳 India, 🇮🇩 Indonesia, 🇻🇳 Vietnam, 🇺🇸 United States, 🇲🇽 Mexico |
| Invasive in | Queensland, Northern Territory, Pacific islands: check local rules before planting |
Is Golden trumpet (allamanda) toxic?
- People: moderately toxic
- Cats: mildly toxic
- Dogs: mildly toxic
- Parts: all parts, milky sap
All parts are poisonous and strongly purgative (hence “cathartica”); the milky sap irritates skin.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Golden trumpet (allamanda)
No well-documented helpful pairing. Group it with plants that like full sun and moderate water.
Questions about Golden trumpet (allamanda)
- How far apart should I plant Golden trumpet (allamanda)?
- About 2 m (6.6 ft) apart, centre to centre. A mature plant spreads 2–4 m (6.6–13 ft).
- Does Golden trumpet (allamanda) need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Golden trumpet (allamanda) need?
- Moderate water. Drought tolerance is low and waterlogging tolerance none.
- How cold-hardy is Golden trumpet (allamanda)?
- It tolerates about 2 °C (36 °F) once established, roughly USDA zone 10.
- When does Golden trumpet (allamanda) flower?
- From about April for 21–39 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Golden trumpet (allamanda) poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs mildly toxic; for people moderately toxic. All parts are poisonous and strongly purgative (hence “cathartica”); the milky sap irritates skin.
- What grows well with Golden trumpet (allamanda)?
- There is no well-documented companion pairing for Golden trumpet (allamanda). Group it with plants that like the same sun (full sun) and water (moderate).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- UF/IFAS Extension tropical and subtropical fruit and landscape publications, University of Florida
- Flora & Fauna Web, National Parks Board, Singapore
- CABI Invasive Species Compendium, CABI
Notes and assumptions
- A scrambling shrub with big buttercup-yellow trumpets most of the year in the tropics; tied to a fence or trellis it climbs to 6 m.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
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