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Commelina communis

Asiatic dayflower

SunFull Sun – Part Shade

Overview

Commelina communis is a sprawling summer annual with succulent, branching stems 8-36 inches (20-90 cm) long that lie along the ground and root at the lower nodes before turning upward. Leaves are lance-shaped, 2-5 inches (5-12 cm) long, with parallel veins and sheathing bases that wrap the stem. Flowers emerge from a folded, heart-shaped green bract: each bloom has two rounded upper petals of bright blue and a smaller, almost colorless lower petal, with yellow stamens at the center. Individual flowers open for only a single morning, giving the plant its common name, but new flowers open in succession from June through October. The flowers are followed by small capsules holding pitted brown seeds. Rooting stems and abundant seed let it spread quickly through gardens and crops, where it tolerates shade and competes with cultivated plants. Broken stem pieces root readily, so cultivation can spread it. The succulent stems wilt fast when pulled but reroot if left on moist soil.

Native Range

Native to eastern Asia, including China, Japan, Korea, and far-eastern Russia. Naturalized across eastern North America, Europe, and elsewhere, growing in gardens, fields, roadsides, stream banks, and moist disturbed ground, mostly below 4,000 feet (1,200 m).

Suggested Uses

Not usually cultivated; it grows as a garden and crop weed, though the blue flowers are sometimes allowed in informal plantings. The young shoots and leaves are eaten as a cooked green in parts of its native range. It is otherwise managed as a weed.

How to Identify

Recognized by two bright blue upper petals and a small whitish lower petal emerging from a folded green bract, on succulent stems that root at the nodes. The lance-shaped leaves have sheathing bases typical of the spiderwort family. Distinguished from Commelina erecta by its trailing, rooting stems and annual habit.

Appearance

Size & Dimensions

Height8" - 3'

Width/Spread1' - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~18 weeks

Summer Fall

Flowers from June through October, with peak bloom in mid to late summer. Each flower lasts only a single morning, but the plant produces a long succession of blooms over several months. Flowering continues until the first frost.

Detailed Descriptions

Flower Description

blue with white

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)

357912

Soil Types

loam clay sand

Drainagemoist

Water & Climate

Water Needs

Medium

Care & Maintenance

Care Guide

Grows in full sun to partial shade on moist, fertile soils and tolerates more shade than many summer weeds. Seeds germinate from late spring onward, and stems root wherever the nodes touch moist soil, so plants spread both by seed and by rooting. Hoeing and pulling can spread it if stem fragments are left behind, since these reroot. It needs no irrigation or feeding and reseeds heavily in gardens and crops. Plants are killed by the first hard frost.

Pruning

Not pruned in the ornamental sense. Removing whole plants, including rooted stem pieces, before seed sets limits spread, since fragments left on moist soil reroot. Cutting back top growth alone does not stop the rooting stems.