Alternanthera denticulata (Lesser Joyweed)

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Alternanthera, Genus, spp., Multiple species,

Genus
Multiple species

joyweeds

Amaranthaceae Tropical and subtropical Americas

Container Friendly

SunFull Sun – Part Shade

WaterMedium

Overview

Alternanthera is a genus of about 80 to 140 annual and perennial herbs in the amaranth family, Amaranthaceae, known as joyweeds and Joseph's coat. Most are low, spreading or mounding plants 4-24 inches (10-60 cm) tall, with paired leaves that in ornamental forms are colored green, burgundy, red, orange, pink, or copper. The flowers are small, whitish, and gathered in stalkless, papery, button-like heads in the leaf axils. Ornamental forms are grown for their colored leaves rather than these small flowers. The genus is native mainly to tropical and subtropical America, with some species in Asia, Africa, and Australia, growing in moist ground, wetlands, and disturbed sites. Several ornamental species, such as A. ficoidea and A. dentata, are grown for colored foliage in bedding and containers, while A. philoxeroides, alligator weed, is an aquatic species that has become a serious invasive in waterways. Alternanthera grows as a tender plant, treated as an annual or houseplant in regions with cold winters. Plants need warmth and bright light to hold their leaf color and turn greener in shade. Frost kills the tender ornamental forms.

Native Range

Alternanthera is native mainly to the tropical and subtropical Americas, with some species in tropical Asia, Africa, and Australia. Plants grow in moist soil, along water margins, and on disturbed ground. Several species have naturalized widely, and A. philoxeroides is invasive in warm wetlands around the world.

Suggested Uses

Grown as edging, carpet bedding, and foliage filler in beds and containers for the colored leaves. Trailing forms suit hanging baskets and window boxes, and some species are used as aquarium and pond plants. Compact kinds are clipped into patterned bedding designs.

How to Identify

Identify Alternanthera by the paired leaves and the small, stalkless, papery flower clusters tucked into the leaf axils rather than held on stalks. Ornamental kinds are recognized by leaves in red, burgundy, copper, or pink, often puckered or narrow. The clover-like white flower heads and jointed, sometimes reddish stems separate the genus from similar amaranths.

Appearance

Size & Dimensions

Height4" - 2'

Width/Spread8" - 2'

Colors

Flower Colors

Foliage Colors

red

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Flowers: June–September

Summer Fall

Flowering occurs through the warm months and nearly year-round in the tropics, with small white papery heads forming in the leaf axils. Each head is short and clover-like. In cool climates ornamental plants are often grown only for foliage and cleared before flowering.

Detailed Descriptions

Foliage Description

green, burgundy, red, orange, pink, or copper

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 5-8 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 - 7.0 (Acidic to neutral)

3579

Soil Types

loam sand

Drainagewell drained

Water & Climate

Water Needs

Medium

Care & Maintenance

Care Guide

Alternanthera species grow in full sun to partial shade in moist, fertile, well-drained soil with a pH near 5.5-7.0. The ornamental forms hold their leaf color in full sun and turn greener in shade. The genus needs warmth and steady moisture and grows outdoors year-round only in USDA zones 10-11. Plants are tender and grown as annuals, houseplants, or stock plants overwintered under glass in colder areas. Trimming keeps the low forms dense and compact. The aquatic species spread rapidly and can choke ponds and slow streams.

Pruning

Ornamental forms are sheared or pinched through the season to keep a low, dense habit and bring out new colored growth. Clearing flower heads keeps growth leafy. Cuttings root quickly and are used to overwinter tender kinds.