Commelina coelestis

Commelina coelestris, Blue Spiderwort or Day Flower, is a near-hardy geophytic perennial from Central America with gorgeous blue three-petaled flowers. The flowers are borne in summer and have yellow anthers creating a stunning contrast against the blue of the flowers. The foliage is tall so a sheltered location is ideal to prevent them getting blown over in the wind. In a wind-free spot and left to their own devices they will flop in on each other and tend to self-support. Or you can position willow or thin hazel wands around them as they grow and they will gather support from these as they develop. In my opinion, they are too 'wild and free' to suffer the formality of staking.

Commelina coelestris needs a well-drained gritty substrate and a sunny aspect. Cut back the foliage after they have flowered and are starting to turn brown. In many locations in the UK, it will be best to unearth the bulbs and store in a cool dry place until the Spring. In some favoured southerly locations or in the sheltered micro-climate of a London garden they can be thickly mulched and left in the ground for next year.