Causonis spp.

Bushkiller

Vitaceae

East and Southeast Asia, Australia, and the Pacific

Attracts Pollinators

SunFull Sun – Part Shade

WaterMedium

HardinessZones 7–10

Overview

Causonis spp. is a genus of climbing plants in the grape family (Vitaceae), split off from Cayratia spp. and found through tropical and warm-temperate Asia, Australia, and the Pacific. The vines climb by branched tendrils, reaching 10-30 feet (3-9 m), with stems that are soft and herbaceous in many species and die back where winters are cold. The leaves are divided into five leaflets arranged like a hand, toothed along the edges and bright green. In summer small greenish-yellow flowers open in flat-topped clusters opposite the leaves, drawing flies and bees, and they ripen into small dark berries that birds carry off. Causonis japonica, sometimes called bushkiller, grows fast and roots from creeping stems, forming dense smothering mats over other plants. This vigour has made it a serious invasive weed in the southeastern United States, where it overruns native vegetation and is hard to remove once rooted. The genus needs warmth and moisture and is killed back by hard frost, so its spread is checked in cold-winter regions.

Native Range

The genus is native to East and Southeast Asia, Australia, and the Pacific islands, growing in forest margins, thickets, and disturbed ground. Causonis japonica ranges widely through Asia and has naturalised as an aggressive weed in parts of the southeastern United States.

Suggested Uses

Within its native range the genus grows in thickets and forest edges and has little deliberate garden use. Where it is naturalised, the focus is on control rather than planting, given its smothering growth. The berries feed birds, which also carry the seed into new ground.

How to Identify

Look for a soft-stemmed climbing vine with leaves divided into five toothed leaflets spread like fingers from a single point. Branched tendrils grow opposite the leaves and coil onto supports. Flat clusters of tiny greenish-yellow flowers appear in summer, followed by small berries that ripen from green through red to black.

Appearance

Size & Dimensions

Height10' - 30'

Width/Spread3' - 10'

Reaches mature size in approximately 2 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Summer

Small greenish-yellow flowers open in summer, generally June to August, in flat-topped clusters set opposite the leaves. The flowers are about 0.1 inch (3 mm) across and draw flies, bees, and other small insects. Dark berries follow over late summer and autumn and are spread by birds.

Detailed Descriptions

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 sand

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

fast; one to two seasons

Care & Maintenance

Care Guide

Plants grow in sun to part shade on moist, fertile, well-drained soil across a pH of about 5.5 to 7.5. Warmth drives fast growth, and in cold-winter areas the topgrowth dies back while the roots survive to resprout. The vines climb readily and need a fence, trellis, or other support, since they will scramble over and smother nearby plants without it. Established plants spread by creeping, rooting stems as well as by seed, which makes them hard to contain. Where a species is invasive, growth is cut back hard and roots dug out to slow its spread. Few pests trouble the vines, which are more often a problem themselves.

Pruning

Vines are cut back through the growing season to hold them in check and clear them off other plants. In cold areas the frost-killed topgrowth is cleared in autumn or late winter. Where the genus is a weed, repeated cutting and digging of the roots is used to weaken and remove it.