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Fallopia spp.

Fallopias

Polygonaceae

Temperate Northern Hemisphere, mainly Asia and Europe

Attracts Pollinators Attracts Butterflies Drought Tolerant

Native to North America

SunFull Sun – Part Shade

WaterMedium · drought-tolerant

HardinessZones 4–9

Overview

Fallopia spp. is a genus of fast-growing herbs, climbers, and woody-based perennials in the knotweed family, Polygonaceae, native across the temperate Northern Hemisphere. It includes Japanese knotweed F. japonica, a stout herbaceous perennial reaching 10 feet (3 m) with hollow, bamboo-like stems; the rampant Russian vine F. baldschuanica, which twines to 40 feet (12 m); and the annual black bindweed F. convolvulus. Plants carry alternate, often heart-shaped leaves and sprays of small white to greenish flowers in late summer and autumn. Several spread by deep rhizomes or seed and are listed as seriously invasive plants in Europe and North America, regrowing from tiny fragments. The aggressive spread of the invasive species and the difficulty of removing them are the main concerns.

Native Range

Native across the temperate Northern Hemisphere, mainly in Asia and Europe, with the climbing false buckwheat F. scandens native to North America. Plants grow on stream banks, waste ground, woodland edges, and disturbed sites.

Suggested Uses

Rarely planted on purpose, with most attention going to controlling the invasive species. The native climbing false buckwheat is occasionally grown in wildlife plantings, and cut young knotweed shoots are eaten as a tart spring vegetable in some regions.

How to Identify

A vigorous herb or twining climber carries alternate, oval to heart- or shield-shaped leaves and a papery sheath wrapping the stem at each node. Sprays of small white to greenish or pink flowers appear in late summer, followed by tiny three-angled fruits that are sometimes winged. Hollow, bamboo-like canes with red-flecked stems mark Japanese knotweed.

Appearance

Size & Dimensions

Height3' - 40'

Width/Spread3' - 15'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Summer Fall

Sprays of small white to greenish flowers open in late summer and autumn, August to October, in branched clusters from the leaf axils and stem tips. The late nectar draws bees and wasps before the plants set small three-angled fruits.

Detailed Descriptions

Flower Description

white to greenish-white, sometimes pink

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-8 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 Range5.0 - 7.5(Neutral)

357912

Soil Types

loam clay sand

Drainageaverage

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-3 years to flowering

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Fallopia spp. grows in full sun to part shade in almost any soil, from dry to moist, and is hardy to about USDA zone 4 (-30°F / -34°C). The rhizomatous species spread fast and are very hard to remove once established. Japanese knotweed and Russian vine are restricted or banned from sale in many regions because of their invasive spread. The plants need almost no care to grow, which compounds the control problem. Even small root or stem fragments can take root and form new plants.

Pruning

Repeated cutting through the season weakens the rhizomes of the invasive species over several years. The annual bindweed is pulled before it seeds. Cut stems and root fragments are disposed of carefully, since they resprout readily.