moonflower (Ipomoea alba, L. 1753)

Identity

As dusk falls, the white trumpet of moonflower (Ipomoea alba L., 1753) opens, remaining open overnight and closing before noon the following day. Also called moonvine, this perennial climber belongs to the morning glory family, Convolvulaceae. Its evening rhythm contrasts with the morning flowering of cultivated blue and purple morning glories. ^{1 2}

Common names can cross botanical boundaries. In metropolitan France, belle-de-nuit usually means the unrelated Mirabilis jalapa; in the French Caribbean, it more often refers to Ipomoea alba. The scientific name identifies the same species across countries, while a shared common name can identify different plants. ⁸

Recognition

Moonflower is a twining vineA climber whose stem winds around a support, without tendrils or adhesive roots.. Its stems contain milky sap and may feel slightly prickly, unlike the smooth stems of some other cultivated morning glories, including Ipomoea tricolor. Heart-shaped leaves, entire or sometimes three-lobed, are 10–20 cm (4–8 in) long and grow along the stems. In one growing season the vine commonly reaches 3–9 m (10–30 ft); lengths over 20 m (66 ft) have been reported in tropical climates where it persists as a perennial. ^{2 3}

The fragrant white flower forms a broad trumpet 8–15 cm (3–6 in) across. It opens within minutes at dusk and closes before noon the next day. This schedule attracts moths rather than daytime insects; cool or overcast weather can keep the flower open longer. ^{3 8}

After flowering, capsules release dark brown to black seeds about 10–12 mm (0.4–0.5 in) long. They can float in seawater for long periods. Buoyant seeds carried between islands by coastal currents help explain the species' wide distribution throughout the tropics. ⁸

Useful taxonomy

POWO/WCVP accepts Ipomoea alba L. Older literature and horticultural catalogs also use other generic names. Important synonyms include:

• Convolvulus aculeatus L., a heterotypic synonymA synonym based on a different nomenclatural type from the accepted name, but treated as the same species. of Ipomoea alba in POWO;
• Calonyction aculeatum (L.) House;
• Ipomoea bona-nox L.;
• Calonyction bona-nox (Spreng.) Bojer.

Calonyction, a name meaning roughly “beautiful at night” in Greek, still appears in older books and catalogs. Current classification places the plant in Ipomoea, subgenus Quamoclit. The name Calonyction aculeatum in a catalog refers to the same species now called Ipomoea alba. ^{1 8}

Habitat and distribution

Its native range is tropical and subtropical America, extending from northern Argentina to southern Mexico and including Florida and the West Indies. It grows along woodland edges, in thickets of seasonally dry forests, beside rivers and on disturbed ground. ^{2 4}

The IUCN assesses Ipomoea alba as Least Concern, reflecting its broad range and stable presence. ⁶

Ornamental planting has introduced moonflower well beyond its original range. It has naturalized in many tropical and subtropical regions, with floating seeds also contributing to dispersal. Invasive alien populations are monitored in South Africa, some Pacific islands, the Galápagos and New South Wales. Such regional invasive status is distinct from garden cultivation elsewhere, where no problem is recorded. ⁴

Life cycle and reproduction

In temperate Northern Hemisphere gardens, flowering generally extends from July to October; in the tropics, it can continue almost all year. Moths, including hawkmoths, are the main pollinators. Their long proboscises fit the flower's elongated tube. ^{3 8}

Propagation is chiefly by seed. The hard seed coat impedes germination unless it is scarified or the seed is soaked for 24 hours beforehand. Summer stem cuttings establish faster when propagating an already flowering plant, because they bypass the seed's dormancy-breaking stage. ^{4 2}

Within its original range the vine is perennial, sometimes with a tuberous rootA swollen root that stores reserves and allows regrowth after a dry period or slight cold damage.. It can regrow after drought or a light frost that destroys its aboveground foliage. That recovery is not assured in cold temperate climates, where treating it as an annual is more reliable than depending on the root to survive. ⁴

Uses and risks

Moonflower is principally an ornamental climber. During a single warm season it can cover a trellis, pergola or fence, and its scent and white flowers suit a night garden planted with other pale, fragrant blooms. ^{2 3}

Its technical history reaches back to approximately 1600 BCE, when Mesoamerican peoples mixed latex from Castilla elastica with juice from Ipomoea alba to make rubber balls and other objects. Sulfur in the vine cross-links the latex, a form of vulcanizationChemical treatment that links natural-rubber chains, making the material more elastic and more resistant to heat. predating Charles Goodyear's 19th-century discovery by several millennia. ⁷

The seeds contain indole alkaloids, including lysergic acid and lysergamide. The ASPCA lists Ipomoea species as toxic to dogs, cats and horses. Ingestion can cause vomiting, and large amounts of seed may cause hallucinations. Keep seeds away from children and domestic animals. ⁵

Varieties, look-alikes and related plants

Seed is commonly sold as Giant White, a sales name for particularly large-flowered plants rather than a distinct, stabilized botanical variety. ²

Potential confusions include:

• Ipomoea tricolor and Ipomoea purpurea, whose colored flowers open by day;
• daturas and Brugmansia, with large, often white, night-opening flowers, but belonging to the Solanaceae and much more toxic in all their parts;
• Mirabilis jalapa, which shares the French name belle-de-nuit in metropolitan France but belongs to another family.

Check the scientific name before buying: morning glories, daturas and Mirabilis jalapa can share common names whose meaning changes between countries. That distinction matters particularly when considering seed toxicity.

Main sources

• Plants of the World Online / Kew, Ipomoea alba L.
• NC State Extension Gardener Plant Toolbox, Ipomoea alba
• Missouri Botanical Garden Plant Finder, Ipomoea alba
• Plants For A Future, Ipomoea alba
• ASPCA, Morning Glory (Ipomoea spp) toxicity entry
• IUCN Red List, Ipomoea alba assessment
• MIT News Office, Mesoamerican rubber processing with Castilla elastica and Ipomoea alba (1999, archived)
• Wikipedia EN, Ipomoea alba