Epilobium brunnescens (New Zealand Willowherb)

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Epilobium, Genus, brunnescens, Species,

Genus & species

New Zealand willowherb

Onagraceae

New Zealand and nearby southern islands

Attracts Pollinators

SunFull Sun – Part Shade

WaterHigh

HardinessZones 6–8

Overview

Epilobium brunnescens is a creeping, mat-forming perennial of the willowherb family, with thread-like stems that trail over the ground and root at the joints to form low carpets only 0.4-2 inches (1-5 cm) deep. The small rounded to oval leaves are 0.1-0.3 inch (3-8 mm) long, opposite, short-stalked, and often bronze-tinted. Tiny solitary flowers about 0.1-0.2 inch (3-5 mm) across, white to pale pink with notched petals, are held above the mat on slender stalks through summer. These are followed by narrow capsules that split to release seeds carried on white hairs. The plant spreads quickly by rooting stems and wind-blown seed, knitting into bare, damp ground. It is low and creeping rather than upright, and forms dense patches that can smother smaller plants. Top growth dies back in hard winters and regrows from the rooted stems.

Native Range

Native to New Zealand and nearby southern islands, where it grows in damp open ground in the mountains. Introduced to Britain and other parts of Europe in the early 20th century, it has naturalised widely on wet, acidic, open ground, spreading along paths, gravel, stream sides, and upland flushes.

Suggested Uses

Occurs as a self-sown plant in damp gravel, path edges, and rock crevices rather than as a chosen ornamental. It can cover bare, wet ground quickly but spreads beyond where it is wanted. Its weedy, invasive habit on acidic ground makes it unsuited to deliberate planting in most gardens.

How to Identify

Recognised by the prostrate, thread-like, rooting stems, the small rounded bronze-tinted leaves 0.1-0.3 inch (3-8 mm) long, and the tiny white to pink notched flowers on slender upright stalks. The creeping, mat-forming habit separates it from the erect, taller native willowherbs. Its small rounded leaves and ground-hugging growth distinguish it from other Epilobium species in damp ground.

Appearance

Size & Dimensions

Width/Spread1' - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~10 weeks

Flowers: June–August

Summer

Flowers through summer, mainly June to August. The small flowers open singly above the mat over several weeks, with capsules ripening from midsummer. Flowering is shorter at high elevations and longer in mild, damp lowland sites. Seed is shed from late summer into autumn.

Detailed Descriptions

Flower Description

white to pale pink

Foliage Description

bronze-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 Range4.5 - 6.5 (Acidic to neutral)

3579

Soil Types

sand peat rocky

Drainagemoist

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Care & Maintenance

Care Guide

Grows in full sun to partial shade on wet to moist, acidic, open ground and tolerates poor, gritty soils. It spreads readily by rooting stems and seed and needs no care to persist where ground stays damp. Dry soils and dense vegetation check it. It establishes from seed in paving cracks, gravel, and the edges of paths and pots, where it can become a persistent weed. Pulling or hoeing removes it, but rooted fragments and the long-lived seed bank allow quick return.

Pruning

No pruning is required. Removing the mats and rooted stems before seed sets limits spread, though fragments left behind re-root. Repeated clearance is needed where it is unwanted in paving, gravel, or pots.