Does it spread aggressively?

Yes, it can self seed quite freely in moist garden conditions.

Can I grow it in a dry spot?

It prefers consistently moist soil and will likely wilt or fail in dry locations.

Plant guide

Smallflower hairy willowherb.

Epilobium parviflorum

Pronounced eh-pih-LOW-bee-um par-vih-FLOR-um

Also known as Hoary Willowherb, Small-Flowered Willow-Herb, Smallflower hairy willowherb

Hoary Willowherb — Photo by Petr Harant (CC BY) via iNaturalist

This hardy perennial is often found growing near water or in damp meadows. It produces lovely, small pink flowers on tall, slender stems. You will find it is quite resilient in the right environment.

Another photo of smallflower hairy willowherb — Photo by zebedeugalinha (CC BY) via iNaturalist

At a glance

Care level: Easy
Plant type: Perennial herb
Light: Full sun to partial shade
Indoor light: Bright indirect
Water: Every 2 to 5 days
Mature size: 30 to 80 cm
Growth rate: Medium
Hardiness: USDA 4 to 9
Bloom time: Mid summer to early autumn

Care

Keep the soil consistently moist to mimic its natural waterside habitat. Watch for wilting if the soil dries out too much. You can trim back dead stems in late autumn to keep the patch tidy.

Watering: Keep the soil damp at all times, as this plant does not tolerate drying out.
Feeding: Apply a balanced liquid fertilizer during the active growing season.
Pruning: Cut the plant back to the ground once it finishes flowering or in late autumn.
Repotting: Repot if the plant becomes root bound or if you want to divide the clump.
Soil: Moist, nutrient rich soil
Soil pH: Neutral to slightly alkaline
Temperature: -20 to 30°C
Humidity: 40 to 80%
Drought tolerance: Low
Lifespan: Perennial, typically 3 to 5 years.
Deer and rabbits: Moderate

Signs it needs repotting

Roots growing out of the drainage holes.
Water draining through the pot too quickly.
The plant becoming root bound and stunted.

Safety

People: The plant is generally considered non toxic but is not intended for culinary use.
Children: The small, fluffy seeds can be a choking hazard if inhaled or ingested in large amounts by small children.
Contact allergens: The stems can be slightly hairy, which may cause minor skin irritation in sensitive individuals.
Airborne allergens: The wind dispersed seeds are attached to fine white hairs that can be a minor respiratory irritant when released in large quantities.
Edibility: While not highly toxic, it is not commonly consumed and should be avoided to prevent potential gastrointestinal upset.

How to identify it

Softly hairy, lance shaped leaves
Small, pale pink four petaled flowers
Tall, erect stems, usually branched in the upper part
Long, slender, pod like seed capsules

Height: 0.3 to 0.8m
Spread: 0.2 to 0.4m
Leaves: green, deciduous
Flowers: pink, purple, 1 to 2cm
Fruit: brown, autumn

Problems to watch for

Rust · Fungal spots may appear on leaves during periods of high humidity and poor air circulation.

By symptom

Plant problems by symptom

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Growing it

Propagation: seed, division
When to plant: spring, autumn
Overwintering: The foliage will die back to the ground in winter. You can cut the dead stems back to the base in late autumn or early spring.
In containers: It grows well in containers if kept in a self watering pot or a tray of water to maintain constant moisture.

Division

1. Dig up the clump in early spring.
2. Gently pull the root mass apart into smaller sections.
3. Replant the sections immediately in moist soil.

Seed

1. Collect seeds in late summer when pods dry.
2. Sow seeds on the surface of moist soil.
3. Keep the soil consistently damp until germination.

Group this plant with other moisture loving species to create a self sustaining bog garden area.

Grows well with

Purple Loosestrife · They share similar moisture requirements and thrive in the same wetland environments.
Marsh Marigold · This plant provides a nice color contrast and enjoys the same boggy soil conditions.

Similar species

Great Willowherb · It is a larger relative that also enjoys damp habitats but has much showier, larger flowers.

Science

Family: Onagraceae
Genus: Epilobium
Order: Myrtales
Class: Magnoliopsida
Native range: Europe, Western Asia, and parts of North Africa.
Conservation: This plant is common and widespread, so it is not currently of conservation concern.

It is a pioneer species that quickly colonizes disturbed, damp ground and riparian zones.

Value to wildlife: nectar source, larval host plant
Pollinators: bees, butterflies, moths
Uses: pollinator garden, wetland restoration, herbal garden

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 1/9
Soil reaction: 6/9
Light: 7/9
Temperature: 5/9
Moisture: 8/9
Nutrients: 5/9

Taxonomy resolved against GBIF.

Questions people ask

Does it spread aggressively?: Yes, it can self seed quite freely in moist garden conditions.
Can I grow it in a dry spot?: It prefers consistently moist soil and will likely wilt or fail in dry locations.

Where the name comes from

The genus name Epilobium comes from the Greek words epi meaning upon and lobos meaning pod, referring to the flower sitting on top of the seed pod. The specific epithet parviflorum means small flowered.

Good to know

It is commonly known as the small flowered hairy willowherb.
The seeds travel long distances on the wind using their tufts of hair.
It thrives in damp soil where other plants might struggle.

Keep your smallflower hairy willowherb growing

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This guide was generated with AI on October 19, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.