Houndstongue (Cynoglossum officinale)

Also known as: Rats and mice, Houndstooth, Common houndstongue, Hounds tongue, Sheep lice, Wood mat

Cynoglossum officinale, commonly known as houndstongue or Rats and Mice, is part of the borage family. It has a strong, unpleasant odor that is believed to repel rats. This invasive and noxious weed is also toxic to livestock.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting Toxicity

Attributes of Houndstongue

Lifespan

Biennial, Annual, Perennial

Plant Type

Herb

Plant Height

30 cm to 91 cm

Spread

30 cm

Leaf Color

Green

Flower Size

5 mm to 9 mm

Flower Color

Purple Red

Images of Houndstongue

Quickly Identify Houndstongue

The plant can be identified by its rough, hairy leaves which resemble a dog’s tongue, hence the common name. Its flowers are small, tubular, and usually reddish-purple, blooming in clusters during late spring to early summer.

Scientific Classification of Houndstongue

Phylum

Vascular plants

Class

Dicotyledons

Order

Boraginales

Family

Borage

Genus

Hound's-tongue

Species

Houndstongue

Planting and Growing of Houndstongue

Care Difficulty

Easy

Watering Schedule

Every 2 days

Sunlight Requirements

Partial sun

Sunshine Duration

6-10 hours

Ideal Temperature

50-77℉

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 Houndstongue?

The ideal watering regime for Cynoglossum officinale involves providing approximately 250 milliliters of water each time. It is crucial to water deeply enough so that the moisture reaches the root zone without water-logging the soil. Allow the top layer of soil to dry out slightly between watering sessions, ensuring the roots have access to air and do not become waterlogged.

What are the symptoms of an underwatered Houndstongue? ›

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

What are the symptoms of an overwatered Houndstongue? ›

How to save an overwatered Houndstongue? ›

What Are the Sunlight Requirements for Houndstongue?

Sunlight Requirements: Partial sun

Duration of light: 4 to 6 hours

This plant thrives in partial sunlight conditions, ideally receiving 4 to 6 hours of light. Under these conditions, photosynthesis is optimized, promoting healthy growth and vibrant flowering.

Ensuring Adequate Sunlight ›

Balancing Indoor and Outdoor Light ›

Reflective Surfaces for Indirect Light ›

What Is the Ideal Temperature Range for Houndstongue?

Ideal Temperature: 50 ~ 77℉

The ideal temperature range for growing Cynoglossum officinale is between 50°F and 77°F. This range ensures optimal growth and development of the plant by providing moderate warmth without overexposure to heat or cold.

What Soil is Best for Houndstongue?

Soil type: Sandy soil, Loam, Calcareous soil

Soil PH: 6.5 ~ 7.5

Cynoglossum officinale thrives in well-drained soil, as it prevents root rot by allowing excess water to exit quickly. This type of soil enhances air circulation around the roots, promoting healthy growth and preventing fungal infections. A soil enriched with organic matter provides essential nutrients for healthy plant development. Organic matter, such as compost, boosts soil fertility, enhances its structure, and encourages the proliferation of beneficial microorganisms. This plant prefers soil that retains moderate moisture without becoming waterlogged. Balanced moisture levels support consistent nutrient uptake and avoid the strain on plants from drought stress, which can otherwise hinder growth and flowering.

How to Fertilize Houndstongue?

Fertilizer type: Balanced

For Cynoglossum officinale, it's essential to use a balanced fertilizer with an NPK ratio of 10-10-10. When applying liquid fertilizer, dilute it to half-strength to avoid over-fertilization, as this plant is sensitive to excessive nutrients. One tablespoon per gallon of water should suffice.

How to Prune Houndstongue?

Pruning Time: Spring, Summer

Begin by assessing the plant structure, identifying dead, damaged, or diseased stems. Start by making clean cuts at the base of undesirable stems to stimulate healthy growth and reduce crowding in the plant’s foliage. Cynoglossum officinale benefits from light shaping to enhance aesthetics. Trim excess growth to maintain the desired plant size, focusing on creating an open structure that facilitates air circulation and light penetration.

How to Propagate Houndstongue plant?

Propagate Time: Late spring, Early summer

Fill the seed tray with potting mix, ensuring it's level and leaving about 1 cm between the mix surface and the tray's top edge. Lightly moisten the mix before sowing seeds.

Scatter Cynoglossum officinale seeds evenly across the moistened potting mix surface. Cover them with a thin layer of additional mix, roughly twice the seeds' diameter.

Place the tray in a sunny location, maintaining a temperature of 15-20°C. Ensure consistent moisture by lightly watering as needed without waterlogging.

How to Repot Houndstongue plant?

Repotting frequency: Every 2-3 years

Repot when the plant shows signs of being root-bound, such as roots emerging from drainage holes or stunted growth. Cynoglossum officinale tends to grow aggressively, so checking every spring for these signals ensures timely repotting.

Choose a pot slightly larger than the current one, with good drainage holes. A terracotta pot is ideal as it allows soil to dry out between waterings, preventing root rot in this moisture-sensitive plant.

Opt for well-draining loamy soil, enriched with organic matter. This soil type ensures proper nutrient intake and prevents over-accumulation of moisture, which is crucial for healthy root development in Cynoglossum officinale.

Toxicity of Houndstongue

Is Houndstongue toxic to humans?

Houndstongue is a plant with a moderate level of toxicity. Its roots, stem, leaves, and flowers are rich in toxic pyrrolizidine alkaloids, which include heliosupine, consolidate, Cynoglossum, and echinate. These compounds can lead to serious health issues when ingested, resulting in side effects like nausea, vomiting, diarrhea, and dehydration. Extended exposure to these alkaloids may lead to liver damage and ultimately liver failure. Additionally, this plant contains oils that can provoke irritation in sensitive skin. The most prevalent side effect is dermatitis, characterized by dry, itchy skin. Continuous contact with this weed may result in a chronic skin condition.

Is Houndstongue toxic to cat?

Houndstongue is indeed poisonous to cats. Felines might accidentally consume various parts of this plant, resulting in potential poisoning due to the harmful nature of all its components. Upon ingestion, affected cats may show symptoms of physical distress, illness, or pain. It is essential for cat guardians to remain observant and ensure that their pets do not come into contact with houndstongue to prevent any adverse situations. Should a cat mistakenly ingest any part of houndstongue, seeking prompt veterinary assistance is crucial to manage the poisoning appropriately.

Is Houndstongue toxic to dog?

Houndstongue is a hazardous plant that poses considerable danger to dogs. Any part of this plant is toxic, meaning that dogs can suffer from poisoning if they ingest it. This usually happens when dogs accidentally consume the plant, often mistaking it for something harmless or out of sheer curiosity. The symptoms resulting from houndstongue poisoning can differ, ranging from gastrointestinal disturbances like vomiting and diarrhea to more severe reactions such as respiratory issues or alterations in heart rate. It is essential for dog owners to stay alert and prevent their pets from entering areas where houndstongue can be found. If there is a suspicion that a dog has consumed houndstongue, seeking immediate veterinary assistance is crucial for achieving the best possible outcome.

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.

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