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Ludwigia, Genus, alternifolia, Species,

Genus & species

seedbox

Onagraceae eastern North America

Attracts Pollinators

SunFull Sun – Part Shade

WaterHigh

HardinessZones 4–9

Overview

Ludwigia alternifolia is an erect herbaceous perennial in the evening-primrose family (Onagraceae), growing 2–4 feet (60–120 cm) tall on smooth, reddish, much-branched stems. The narrow, lance-shaped leaves are arranged alternately along the stems, 1.5–4 inches (4–10 cm) long, and often flush red in autumn. From early to late summer it bears single yellow flowers in the upper leaf axils, each with four broad petals about 0.5 inch (12 mm) across; the petals drop within a day, so flowers are short-lived. The flowers are followed by the feature that gives the plant its common name — squarish, box-shaped seed capsules about 0.25 inch (6 mm) on each side, with a rounded base and a small pore at the top, that turn brown and rattle when shaken. It grows in consistently wet ground including marsh edges, wet meadows, ditches, swamp margins, and pond shores across eastern North America. The brief, scattered flowers give a limited display, with the cubic seedpods being the longer-lasting feature. It needs wet soil and does poorly where the ground dries out.

Native Range

Ludwigia alternifolia is native to eastern North America, from southern Ontario and New England south to Florida and Texas and west to the eastern Great Plains. It grows in wet habitats throughout the eastern and central United States.

Suggested Uses

Ludwigia alternifolia is used in rain gardens, wetland restorations, and the moist margins of ponds and streams. Its boxy seed capsules supply texture and feed seed-eating birds into winter. It naturalizes readily where soils remain wet.

How to Identify

Identify Ludwigia alternifolia by its branched reddish stems, alternate lance-shaped leaves, and single yellow four-petaled flowers in the upper leaf axils. The surest mark is the fruit: a hard, squarish seed capsule about 0.25 inch (6 mm) per side with a small opening at the top that rattles when dry. The cubic capsules and alternate leaves separate it from other Ludwigia species with opposite leaves or elongated pods.

Appearance

Size & Dimensions

Height2' - 4'

Width/Spread1' - 2'

Colors

Flower Colors

yellow

Foliage Colors

green

Fall Foliage Colors

red

Bloom Information

Bloom Period

~8 weeks

Flowers: June–August

Summer

Yellow flowers open from June through August, one or a few at a time in the leaf axils. Each flower lasts only about a day, dropping its petals by afternoon, but the plant continues opening new flowers over roughly 8 weeks. The boxy seed capsules form through late summer and persist into winter.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-12 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 silt clay

Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Care & Maintenance

Care Guide

Ludwigia alternifolia grows in full sun to part shade in wet, fertile soils — loam, silt, or clay — that stay moist or flooded through the growing season. It suits rain gardens, pond and stream margins, and the wet zones of native plantings, and tolerates standing water. It does not tolerate prolonged drought and declines on dry sites. It needs no fertilizer in fertile wetland soil and self-sows where the ground stays wet. Stems can be left standing through winter for the rattling seed capsules.

Pruning

No pruning is needed. Stems are cut back to the ground in late winter or early spring, or left standing for the seed capsules and winter form. Self-sown seedlings can be thinned where the plant spreads further than wanted.