Poison hemlock (Conium maculatum)

Also known as: Wild Hemlock, Devil's bread, Poison parsley

Poison Hemlock (Conium maculatum) is an extremely toxic plant that often deceives livestock due to its leaves, which closely resemble those of carrots and parsley. Ingestion of this plant can be fatal.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting Toxicity

Attributes of Poison hemlock

Lifespan

Biennial, Perennial

Plant Type

Herb

Plant Height

1.5 m to 2.5 m

Spread

1 m

Leaf Color

Green

Flower Size

10 cm to 15 cm

Flower Color

White

Images of Poison hemlock

Quickly Identify Poison hemlock

Hollow stem with purple blotches

Finely divided, lacy leaves reminiscent of a carrot top

Distinctive white flowers in umbrella-like clusters with a central purple flower

Green fruit maturing to gray-brown ovoid shape with wavy ribbing

Large, intricately dissected leaves with 3-4 pinnate divisions

Scientific Classification of Poison hemlock

Phylum

Vascular plants

Class

Dicotyledons

Order

Apiales

Family

Umbellifers

Genus

Poison hemlocks

Species

Poison hemlock

Planting and Growing of Poison hemlock

Care Difficulty

Hard

Watering Schedule

Every 2 days

Sunlight Requirements

Partial sun

Sunshine Duration

4-8 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 Poison hemlock?

Conium maculatum prefers soil that is kept evenly moist but not waterlogged. Generally, aim for around 300 milliliters per watering, ensuring the water reaches the root zone but does not accumulate at the surface or the base of the container. Consider factors like humidity and sunlight in your environment to adjust accordingly.

What are the symptoms of an underwatered Poison hemlock? ›

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

What are the symptoms of an overwatered Poison hemlock? ›

How to save an overwatered Poison hemlock? ›

What Are the Sunlight Requirements for Poison hemlock?

Sunlight Requirements: Partial sun

Duration of light: 4 to 6 hours daily

Conium maculatum thrives in partial sun, ideally receiving 4 to 6 hours of indirect and morning direct light. This balance promotes its health by aiding in nutrient synthesis, thus resulting in strong growth and flowering, reducing the risk of scalds.

What is the ideal light condition for Conium maculatum? ›

How can you achieve the ideal lighting for Conium maculatum? ›

What benefits does Conium maculatum receive from ideal lighting? ›

What Is the Ideal Temperature Range for Poison hemlock?

Ideal Temperature: 60 ~ 75℉

For ideal growth, Conium maculatum prefers a temperature range between 60°F and 75°F. This range provides optimal conditions for its metabolic processes and overall development. Within these temperatures, the plant finds the right balance of warmth without being exposed to extreme heat, which ensures healthy leaf growth and flowering.

What Soil is Best for Poison hemlock?

Soil type: Loam, Sandy loam, Calcareous soil

Soil PH: 6.5 ~ 7.5

Conium maculatum thrives in nutrient-rich soils that provide essential minerals and nutrients for optimal growth. Ensuring the soil is fertile promotes robust plant health and vibrant foliage. Adequate drainage is crucial for this plant to prevent waterlogging, which can lead to root rot. A well-drained soil supports healthy root systems and overall plant vigor. While good drainage is essential, maintaining a consistent level of soil moisture ensures Conium maculatum receives enough water, crucial for its growth during dry periods.

How to Fertilize Poison hemlock?

Fertilizer type: Balanced

For Conium maculatum, the fertilizer amount should be carefully measured. Use a diluted liquid fertilizer at half strength to avoid any risk of over-fertilization. If using a granular slow-release fertilizer, apply approximately 50 grams per square meter to maintain optimal nutrient levels.

How to Prune Poison hemlock?

Pruning Time: Spring, Summer, Autumn

Begin by identifying the stems that are dead, damaged, or diseased. Conium maculatum, or poison hemlock, can grow quite large and unruly, so it's crucial to target these sections first. Use clean, sharp pruning shears to cut back any unwanted stems at their base. Be cautious to avoid touching your face or skin after handling, as the plant is toxic. Dispose of all pruned material promptly and safely to prevent accidental contact, as Conium maculatum is highly poisonous to humans and animals.

How to Propagate Poison hemlock plant?

Propagate Time: Spring, Early spring

Scatter the Conium maculatum seeds evenly over the surface of a filled seed tray. Lightly cover them with a thin layer of soil and water gently. Ensure that the soil is kept moist but not overly wet during the germination period.

Place the seed tray in a spot that receives indirect sunlight. Too much direct sunlight can dry out the seeds or seedlings, while too little light can slow down germination and growth.

Once the seedlings have grown two sets of true leaves, they can be gently transplanted into individual pots with more potting soil. Handle the seedlings carefully to avoid damaging the stems and roots.

How to Repot Poison hemlock plant?

Repotting frequency: Every two years

Conium maculatum, commonly known as Hemlock, signals its need for repotting through several signs. Look for roots growing out from the drainage holes, slow growth, or if the soil appears compacted. Spring and Autumn are ideal times since the plant is less stressed and can establish itself better in the new soil.

Select a pot that is only slightly larger, about 1-2 inches bigger in diameter than the current one. Ensure it has drainage holes to prevent waterlogging, which can lead to root rot. A breathable material like terracotta is preferable as it allows for air circulation, which benefits root health.

Opt for a well-drained potting mix. A blend that includes sand, perlite, or pumice can ensure good drainage and aeration. Such a mixture helps mimic its natural habitat, reducing the chances of root diseases and allowing for proper root development.

Toxicity of Poison hemlock

Is Poison hemlock toxic to humans?

Consuming any portion of poison hemlock can lead to serious consequences, even if just a small quantity is ingested. Its potent toxin specifically targets the nervous system, disrupting the transmission of nerve impulses to muscles. Symptoms generally manifest within an hour of consumption and may include muscle pain and/or weakness, loss of speech, excessive salivation, initially rapid then decreased heart rate, tremors, dilated pupils, gastrointestinal discomfort, and in some cases, unconsciousness. In severe instances, it may lead to kidney or respiratory failure, long-term damage to both the nervous system and muscles, and ultimately death. Poison hemlock is often found growing near roadsides and in waste areas, and it has previously been mistaken for wild parsnip, which is a common cause of poisoning.

Is Poison hemlock toxic to cat?

As its name implies, poison hemlock (Conium maculatum) is highly poisonous to felines and can lead to fatality upon ingestion of even a minuscule quantity. If a cat comes into contact with this toxic plant, it is crucial to take them to an emergency veterinary facility immediately for urgent care to avert severe lasting health issues, such as paralysis. The plant's delicate, feathery leaves could attract cats, making them prone to playful interactions!

Is Poison hemlock toxic to dog?

Poison hemlock, as its name suggests, poses a significant hazard to dogs due to its high toxicity levels. If you suspect that your dog has ingested any part of this plant, it is imperative to seek veterinary assistance immediately. Every part of the hemlock plant harbors a variety of alkaloid toxins. Ingestion can lead to a range of alarming symptoms such as vomiting, diarrhea, muscle spasms, cramping, elevated heart rate, increased respiratory rate, seizures, and, in severe instances, death. Even minuscule amounts of poison hemlock can cause serious harm to a dog. Fortunately, the plant's intensely bitter flavor discourages dogs from consuming it.

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.