To provide Epilobium hirsutum with the best lighting conditions, ensure it receives about 4 to 6 hours of sunlight daily. This can be achieved by placing the plant near a south-facing window or in a garden where it gets enough natural light without excessive midday sun exposure.

Hairy willowherb (Epilobium hirsutum)

Also known as: Great willowherb

Hairy willowherb (Epilobium hirsutum) is a challenging weed to control. While it isn't toxic, its sale or distribution has been prohibited in certain regions. The reason for this is its rapid and dense growth, which can overtake and eliminate native plant species, thereby disrupting local ecosystems.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting Toxicity

Attributes of Hairy willowherb

Lifespan

Perennial, Annual

Plant Type

Herb

Plant Height

50 cm to 1.8 m

Spread

1 m

Leaf Color

Green

Flower Size

2.5 cm

Flower Color

Pink Purple Red

Images of Hairy willowherb

Quickly Identify Hairy willowherb

Up to 6 feet tall (1.8 meters) with dense soft hairs covering stems and leaves.

Saucer-shaped rose-pink flowers, 3/4 inch across (1.9 cm), with white centers and distinctive 8 stamens.

Dehiscent seed pods, 1-3 inches long (2.54-7.62 cm), releasing wind-dispersed seeds with white hair tufts.

Opposite lanceolate leaves, 2-4 inches long (5-10 cm), densely hairy, toothed, and serrated.

Erect, highly branched stems up to 5 feet tall (150 cm) with abundant soft hairs and reddish color.

Scientific Classification of Hairy willowherb

Phylum

Vascular plants

Class

Dicotyledons

Order

Myrtales

Family

Evening primrose

Genus

Willowherbs

Species

Hairy willowherb

Planting and Growing of Hairy willowherb

Care Difficulty

Easy

Watering Schedule

Every 2 days

Sunlight Requirements

Full sun

Sunshine Duration

6-10 hours

Ideal Temperature

60-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

6.5-7.5

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Hairy willowherb?

For optimal growth, Epilobium hirsutum prefers being well-hydrated but not waterlogged. Water until the soil is damp but not soggy, ensuring at least 500 milliliters per session to sufficiently reach the root system.

What are the symptoms of an underwatered Hairy willowherb? ›

What should I do if my Hairy willowherb is not getting enough water? ›

What are the symptoms of an overwatered Hairy willowherb? ›

How to save an overwatered Hairy willowherb? ›

What Are the Sunlight Requirements for Hairy willowherb?

Sunlight Requirements: Full sun, Partial sun

Duration of light: 4-6 hours daily

Epilobium hirsutum thrives in full sun to partial sun, benefiting from 4-6 hours of sunlight daily. This light range ensures vibrant foliage, optimum growth conditions, and abundant flowering, reflecting its natural habitat preferences.

Optimal light amount ›

Utilizing natural sunlight ›

Benefits of ideal lighting ›

What Is the Ideal Temperature Range for Hairy willowherb?

Ideal Temperature: 60 ~ 75℉

The ideal temperature range of 60 to 75 °F for Epilobium hirsutum is crucial for optimal growth and flowering. Within this range, the plant can efficiently photosynthesize and maintain its metabolic processes. This range ensures that enzymes and cellular structures remain functional, promoting healthy development. Deviating from this range might result in decreased growth rate and sub-optimal health.

What Soil is Best for Hairy willowherb?

Soil type: Loam, Sandy loam, Clay soil, Peat soil

Soil PH: 6.5 ~ 7.5

Epilobium hirsutum thrives in soils with good moisture retention properties, which help keep the roots hydrated even in drier conditions. This prevents wilting and supports lush growth. Rich in organic matter, the ideal soil promotes robust growth and vibrant blooms by supplying essential nutrients continuously. This nutrient supply is crucial for the plant's overall health. While it enjoys moisture, the plant also needs soil that prevents waterlogging, which can lead to root rot. Well-draining soil ensures root systems stay healthy and oxygenated.

How to Fertilize Hairy willowherb?

Fertilizer type: Balanced

Epilobium hirsutum, commonly known as Great Willowherb, requires balanced fertilization. A general-purpose liquid fertilizer should be diluted to half strength, with approximately 100 ml per plant during the growing season to avoid nutrient burn.

How to Prune Hairy willowherb?

Pruning Time: Spring, Summer, Autumn

Focus on removing dead, damaged, or diseased stems by cutting them back to their base. This encourages regrowth and helps the plant maintain a tidy and vigorous appearance. Regularly shape the plant by trimming back overgrown sections to control its size and promote air circulation. This helps to prevent fungal infections and maintain aesthetic appeal. After the flowering season, cut back spent flower stalks to encourage further blooming and manage seed dispersal, keeping the plant's vigor and enhancing garden tidiness.

How to Propagate Hairy willowherb plant?

Propagate Time: Spring, Early summer, Autumn

Sow the seeds directly onto the surface of moistened compost in the seed trays. Gently press them into the soil, but do not cover them completely, as they need light to germinate. Keep the soil consistently moist but not waterlogged.

Select healthy, non-flowering stems and make a clean cut using pruning shears. Remove the lower leaves and dip the cut end into a rooting hormone to encourage root growth. Plant the cuttings in a well-draining potting mix and water them lightly.

Carefully dig up mature plants, taking care not to damage the root system. Separate the root clump into smaller sections, ensuring each section has a portion of roots attached. Replant the divisions at the same depth at which they were growing originally.

How to Repot Hairy willowherb plant?

Repotting frequency: Every 2-3 years

Look for signs like roots growing out of the drainage holes or soil drying out more quickly than usual. These indicate that the plant is outgrowing its current pot and needs more space to thrive.

Select a pot that is one size larger than the current one, which helps the plant to expand and improves aeration. A pot with drainage holes is essential to prevent waterlogging, as this plant enjoys moist but not soggy conditions.

Opt for a moisture-retentive, fertile soil mix which provides adequate nutrients and holds moisture well. This is ideal as the plant thrives in moist conditions and rich soil that supports vigorous growth.

Toxicity of Hairy willowherb

Is Hairy willowherb toxic to humans?

The hairy willowherb is recognized as an extremely toxic plant, capable of inducing severe health issues when consumed. While the leaves are noted for their toxicity, it is possible that the entire plant could also pose a risk. Although the specific toxic agent remains unidentified, multiple reports have highlighted its hazardous nature. One report details a case involving a 3-year-old boy who fell into a coma and experienced epileptiform seizures after ingesting the leaves of the hairy willowherb. Furthermore, research has indicated that this plant can accumulate toxins and heavy metals from its surroundings.

Is Hairy willowherb toxic to cat?

Hairy willowherb exhibits a moderate degree of toxicity, potentially posing health risks to feline companions. If cats inadvertently consume any parts of the plant, especially the leaves, they are at risk of poisoning. After ingestion, affected cats may display signs of physical distress that require urgent attention. Since the toxic effects can lead to various detrimental impacts on a cat's health, it is essential to monitor for any indications of illness and to promptly obtain veterinary assistance. Swift and suitable medical treatment is crucial to alleviate symptoms and safeguard the wellbeing of the affected feline.

Is Hairy willowherb toxic to dog?

Hairy willowherb presents a moderate toxicity hazard for dogs. Canines could inadvertently consume various parts of the plant, especially the leaves, which are recognized for their toxic properties. If a dog ingests hairy willowherb, it may display symptoms that suggest poisoning. Dog owners must be attentive and restrict their pets from entering regions where hairy willowherb flourishes to prevent accidental ingestion. Should a dog exhibit signs of poisoning after eating hairy willowherb, it is vital to obtain immediate veterinary assistance since swift treatment is essential for recovery.

WARNING

The judgment on toxicity and danger is for reference only. We DO NOT GUARANTEE any accuracy of such judgment. Therefore, you SHALL NOT rely on such judgment. It is IMPORTANT TO SEEK PROFESSIONAL ADVICE in advance when necessary.