At a glance
RECORDED PROFILE DATA- Scientific name
- Angraecum eburneum Bory
- Name status
- Accepted
- Native region
- Aldabra, Comoros, Madagascar, Mauritius, Réunion, Seychelles
- Growth habit
- Lithophytic / epiphytic monopodial orchid
- Cultivation temperature group
- Warm (minimum ~15 °C, RHS hardiness H1a)
Names and Taxonomy
Angraecum eburneum Bory (1804) is the accepted name for the “Ivory Angraecum” or “comet orchid”. The name is listed as accepted by Kew’s Plants of the World Online [1] and the original publication is recorded in the International Plant Names Index [3]. Synonymous scientific names recorded for this taxon include Limodorum eburneum (Bory) Willd., Angorchis eburnea (Bory) Kuntze, and older epithets such as Angorchis superba and Angorkis brongniartiana (see IPNI [3]). Common English names documented in horticultural sources are “Ivory Angraecum”, “Ivory Star Orchid” (Growli [4]) and “comet orchid” (RHS [5]).
How to Identify This Species
This is a large, monopodial orchid that can reach 0.5–2 m in height when mature (RHS [5]; IOSPE [6]). Stems are erect, sometimes branching with age, and bear two ranks of stiff, leathery, linear leaves that may grow 3–40 cm long (IOSPE [6]). The plant is lithophytic or epiphytic, attaching its roots to bark or rock surfaces (Cambridge [7]).
Inflorescences are axillary, up to about 120 cm long, and bear 10–15 (sometimes more) waxy flowers (RHS [5]). Individual flowers are approximately 7.5 cm (3 in) across, with a green‑white perianth and a prominent green nectar spur about 7 cm long (IOSPE [6]). The lip is inverted and white, creating the characteristic “up‑side‑down” appearance (Cambridge [7]). Flowers are strongly scented with a gardenia‑like fragrance that intensifies at night (RHS [5]; Cambridge [7]).
Because several Angraecum species share a similar fan of leaves, the combination of very large flowers, a long green spur, and nocturnal fragrance is the most reliable field character for A. eburneum.
Native Range and Habitat
According to Kew’s distribution data, the species occurs naturally in the western Indian Ocean islands: Aldabra, Comoros, Madagascar, Mauritius, Réunion and Seychelles [1][2]. It grows in wet tropical biomes, typically as a lithophyte on rocks or as an epiphyte on tree trunks in lowland forest up to about 750 m elevation (POWO [1]; IOSPE [6]). The habitat is humid, with consistent moisture and warm temperatures.
Species‑Specific Care
| Factor | Documented guidance | Source |
|---|---|---|
| Light | Very bright light, 30 000–35 000 lux; at least 4–6 h of direct sun, screened from harsh midday rays | Growli [4] |
| Temperature | Warm conditions; minimum night temperature around 15 °C (hardiness rating H1a). Typical growing range 16–30 °C. | RHS [5]; Orchid.guru [9] |
| Watering | Water when the medium is almost completely dry, roughly every 5–7 days in average conditions; ensure thorough drainage and never let roots sit in water. | Growli [4] |
| Humidity | Maintain 60 %–80 % relative humidity; good air movement is beneficial. | Orchid.guru [9]; RHS [5] |
| Growing medium | Well‑draining mix such as coarse bark, perlite or a specialist orchid medium; the plant also thrives mounted on cork bark or tree‑fern slab. | Orchid.guru [9]; Growli [4] |
| Fertilization | Balanced, water‑soluble fertilizer applied weekly during active growth. | RHS [5] |
| Seasonal changes | No enforced rest period; keep watering and feeding year‑round, but slightly reduce in the coolest months if temperature approaches the minimum. | Growli [4] |
In practice, the most critical factors are providing strong, filtered light and preventing water‑logged roots. Because the orchid is accustomed to a consistently moist but well‑aerated environment in the wild, a dry‑through period should be avoided.
Flowering and Pollination
In its native range the plant flowers in the early winter months (approximately June–August in the southern hemisphere, or October–February in the northern hemisphere) [5][12]. Flowers are long‑lasting, remaining viable for several weeks. The strong nocturnal gardenia fragrance attracts hawk moths (Sphingidae), which act as the primary pollinators, inserting their proboscis into the long spur to reach nectar (Cambridge [7]).
Evidence and Limitations
Most morphological and ecological information comes from horticultural descriptions (RHS, Growli, IOSPE) and Kew’s distribution database. Precise temperature minima, optimal humidity ranges and watering intervals are based on grower observations rather than controlled experiments, so growers should adjust based on local conditions. No formal conservation assessment (e.g., IUCN) was located in the available sources.
Frequently asked questions
What light level does Angraecum eburneum need?
It prefers very bright light of about 30 000–35 000 lux, with at least 4–6 hours of direct sun filtered from the harshest midday rays [4].
How often should I water Angraecum eburneum?
Water when the growing medium is almost completely dry, roughly every 5–7 days in average conditions, and ensure the pot drains fully [4].
What temperature range is suitable for this orchid?
It thrives in warm conditions, with a minimum night temperature around 15 °C (hardiness rating H1a) and a typical growing range of 16 °C–30 °C [5][9].
FOLLOW THE EVIDENCE
Sources & references
- Plants of the World Online – Angraecum eburneum subsp. eburneum, Kew Science, https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77167551-1
- Plants of the World Online – Angraecum eburneum subsp. superbum, Kew Science, https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77188785-1
- International Plant Names Index – Angraecum eburneum, IPNI, https://www.ipni.org/n/616096-1
- Growli – Angraecum eburneum care guide, Growli, https://www.getgrowli.app/plant-care/angraecum-eburneum
- RHS – Angraecum eburneum details, Royal Horticultural Society, https://www.rhs.org.uk/plants/1284/angraecum-eburneum/details
- IOSPE PHOTOS – Angraecum eburneum, IOSPE, https://orchidspecies.com/angeburneum.htm
- Cambridge University Botanic Garden – Angraecum eburneum, Cambridge Botanic Garden, https://www.botanic.cam.ac.uk/the-garden/plant-list/angraecum-eburneum/
- Smithsonian Gardens – Angraecum eburneum, Smithsonian Institution, https://gardens.si.edu/collections/explore/object/ofeo-sg_2018-0919A
- Orchid.guru – Angraecum eburneum, Orchid.guru, https://www.orchid.guru/content/orchids/a/angraecum/eburneum/
