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Commelina cyanea

scurvy weed

Commelinaceae Eastern Australia

Attracts Pollinators Container Friendly

SunPart Shade – Full Shade

WaterMedium

HardinessZones 9–11

Overview

Commelina cyanea, called scurvy weed, is a sprawling perennial herb in the family Commelinaceae native to eastern Australia. Soft, trailing stems 12-40 inches (30-100 cm) long root at the nodes where they touch the ground, forming a low, spreading mat 6-12 inches (15-30 cm) high. The smooth, lance-shaped leaves are 1-3 inches (3-8 cm) long with sheathing bases that clasp the stem. Bright blue three-petalled flowers about 0.4-0.6 inch (10-15 mm) wide open a few at a time from a folded green bract, each lasting a single day, over a long season from spring into autumn. Small capsules follow and release several seeds. The species grows in moist, shaded ground in forest, woodland, and disturbed sites, spreading readily by rooting stems. In gardens it serves as a quick groundcover in shade but can travel beyond its intended area, and frost cuts back the soft top growth. The young leaves and stems have a long history of use as a cooked or raw green.

Native Range

Commelina cyanea is native to eastern Australia, from Queensland through New South Wales to Victoria. It grows in moist, shaded forest floors, creek margins, woodland, and disturbed urban ground, often forming spreading patches.

Suggested Uses

Grown as a shade groundcover, in moist rockeries, and in container and hanging displays where its trailing stems spill over edges. Suited to damp, shaded courtyards and the fronts of woodland borders. Spaced 12-18 inches (30-45 cm) apart for cover.

How to Identify

Recognised by soft, trailing stems that root at the nodes and bear smooth lance-shaped leaves with stem-clasping sheaths. The three-petalled flowers are clear blue, about 0.4-0.6 inch (10-15 mm) across, and emerge from a folded leaf-like bract, opening for only a day. The low, mat-forming habit and day-long blue flowers separate it from upright relatives.

Appearance

Size & Dimensions

Height6" - 1'

Width/Spread2' - 5'

Colors

Flower Colors

blue

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~20 weeks

Spring Summer Fall

Flowering extends over a long season from spring through autumn, mainly October to March, with a few flowers open on any given day. Each clear blue bloom lasts a single morning before closing. The flowers draw small native bees in shaded, sheltered positions.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 3-6 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

Frost Tolerance

tender

Time to Maturity

1 year

Care & Maintenance

Care Guide

Grows in part to full shade on moist, humus-rich loamy or clay soils, and tolerates a range of pH. Even soil moisture sustains lush growth, while extended dryness causes the stems to wilt and brown. The trailing stems root as they spread, so the plant fills shaded ground quickly and may need containing at the edges. Frost burns the soft growth, which regrows from the base in spring in milder areas. Light feeding in spring supports leafy cover. Cutting back straggly stems keeps the patch dense.

Pruning

Cutting or mowing straggly stems through the growing season keeps the mat low and dense and curbs its spread. Stems that root beyond the intended area can be pulled or trimmed at any time. No structural pruning is needed.

Pruning Schedule

summer