Morning Glory

Where it grows

Ipomoea is a huge genus, with morning glory species native to tropical and subtropical regions worldwide. The common purple morning glory comes from Mexico and Central America. Heavenly Blue, the iconic mid-blue cultivar, was developed in Japan, where morning glory (asagao) has been bred since the Edo period for an extraordinary variety of forms.

How to recognise it

A twining annual or short-lived perennial vine that can climb three to four metres in a single season, with heart-shaped leaves and large funnel-shaped flowers up to ten centimetres across. The flowers open in the morning, fade in heat or afternoon sun, and produce hard, segmented seed capsules.

Garden & cultural uses

In Japan, asagao is an entire genre of horticultural artistry, with hundreds of named cultivars showing fringed, doubled, and miniature flowers. Some species — notably I. tricolor and Hawaiian baby woodrose (Argyreia nervosa) — contain ergoline alkaloids and have a long history of ritual use in Mexican Indigenous practice.

In ecology

Morning glories twine anticlockwise (when viewed from above), a fixed handedness genetically encoded and used in plant-biology classrooms to demonstrate circumnutation.