Poison Hemlock

conium maculatum

Also known as: ["Poison Parsley","Spotted Coriander","Beach Hemlock"]

Family: Apiaceae Genus: Conium Category: Herbs & Weeds

Overview

A highly toxic biennial herb with finely divided leaves and small white flowers, native to Europe and North Africa.

Benefits & Perks

["wildlife attractant (bees, butterflies, birds)"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Apiales
Family: Apiaceae
Genus: Conium
Botanical Name: Conium maculatum

Plant Characteristics

Basic Information
  • Category: Herbs & Weeds
  • Suitable Location: garden bed in a location with good air circulation
  • Suitable For:
    Collectors & Enthusiasts Wildlife Supporters
  • Is Weed: No
  • Allergenicity: low
Environmental Needs
  • Climate: {"temperatureRange":"5–30°C"}
  • Hardiness: {"zones":"4–9"}
  • Misting: rarely required, only if ambient humidity is very low
  • Drainage: Moderately well-draining; avoid waterlogged conditions.
  • Soil Type: Rich, moist but well-draining soil; prefers loamy or sandy soil with organic matter.
Maintenance Level
  • Maintenance Level: moderate
  • Toughness Level: moderate
  • Pruning Frequency: As needed; remove spent flower stalks after flowering to encourage new growth.
  • Pruning Intensity: Light pruning; avoid heavy cuts unless removing dead or diseased parts.
Care Details

Ideal Sunlight Coverage:
Full sun to partial shade; 6–8 hours of direct sunlight per day, with some afternoon shade in hot climates.

Sunlight Tolerance Tips:
Acclimate plants gradually to direct sunlight; protect from intense midday sun to prevent scorching; adjust placement based on indoor/outdoor conditions.

Warning Signs: Yellowing leaves, root rot, or stunted growth indicate poor soil conditions or overwatering.

Care Requirements

Care Difficulty
expert only

moderate

Sunlight

full sun to partial shade

Rotate plant for even light exposure; use sheer curtains to filter intense sunlight; avoid placing in drafty areas.

Watering

every 7–10 days, allowing soil to dry slightly between waterings

Water thoroughly but infrequently; ensure soil dries between waterings; avoid waterlogging.

Soil

well-drained, fertile loam

pH: Slightly acidic to neutral (pH 6.0–7.0).

Ensure soil is not compacted; avoid heavy clay soils; maintain consistent moisture.

Temperature

Prefers cool to moderate temperatures (60–75°F or 15–24°C); tolerates cooler nights but avoids extreme heat.

Monitor temperature fluctuations; adjust watering in extreme heat or cold; protect from drafts.

Fertilizing

every 4–6 weeks during active growth with a balanced liquid fertilizer

Apply fertilizer after watering to prevent root burn; flush soil occasionally to prevent salt buildup; reduce feeding in dormancy.

Propagation

Methods

Seed or root division; stem cuttings can also be used but are less common.

Step-by-Step Propagation Guide
  1. Prepare medium.
  2. Sow seeds or take cuttings.
  3. Provide warmth and humidity.
  4. Transplant once rooted.

Best Time: Spring or early summer when the plant is actively growing.

Environment

Warm, humid environment with indirect light; maintain consistent moisture.

Medium

Well-draining seed starting mix or a mix of peat and perlite for cuttings.

Hormone

Rooting hormone is optional but can improve success rates for cuttings.

Timeline

Seeds germinate in 2–4 weeks; cuttings root in 3–6 weeks and may take several months to establish.

Tools Needed

Pruning shears, rooting hormone, pots, misting spray bottle.

Quick Tips

Use fresh seeds for best germination; keep cuttings out of direct sun; maintain consistent moisture.

Pruning & Repotting

Pruning Guide
Method

Snip off dead or yellowing leaves; trim back overgrown stems to maintain shape.

Pruning Plan

Minimal pruning needed; focus on removing dead or damaged foliage to maintain plant health.

Tools

Pruning shears, gloves.

Checklist

Wear gloves; sterilize tools; remove dead/damaged parts; avoid over-pruning.

Repotting Guide
Best Season

Early spring before new growth begins.

Pot Size

Increase pot size by 1–2 inches in diameter; ensure good drainage holes.

Method

Remove plant gently; trim roots if necessary; repot in fresh, well-draining soil with a slightly larger pot.

Suggestions

Repot every 2–3 years or when roots fill the container; beneficial for container-grown plants to refresh soil.

Checklist

Choose appropriate pot; prepare new soil; handle roots carefully; water after repotting.

Advanced Care Tips

Watering Mastery
Watering Checklist

Check soil moisture; water deeply; ensure drainage; avoid wetting leaves.

How to Apply Water Properly

Water at the base of the plant, ensuring moisture reaches the root zone; allow excess water to drain away; water in the morning to reduce evaporation.

Pro Tip: Use a watering can with a narrow spout to direct water to the roots without wetting foliage.
Watering Schedule Tips

Water deeply once the top inch of soil is dry; reduce frequency in winter to prevent root rot.

Soil Improvement

Add compost or well-rotted manure to enhance fertility; mix in perlite or sand to improve drainage.

Temperature Stress Management
Signs of Temperature Issues

Wilting, yellowing leaves, or stunted growth in excessive heat; leaf drop or browning in cold stress.

Cold Stress

Low temperatures slow growth and can cause leaf damage or dieback; frost can be lethal.

Solution: Provide frost protection in cold climates; move potted plants indoors during freezes; use mulch to insulate roots.

Hot Stress

Excessive heat leads to wilting, leaf scorch, and reduced vigor; may cease flowering.

Solution: Provide shade during peak heat; increase watering; use mulch to retain soil moisture.

Fertilizing Guide
Fertilizing Checklist

Check fertilizer type; dilute correctly; apply during active growth; avoid winter feeding.

Fertilizing Method

Use a balanced liquid fertilizer diluted to half strength every 4–6 weeks during the growing season (spring to early fall); avoid fertilizing in winter.

Common Problems & Solutions

Yellowing of leaves in Conium maculatum can indicate nutrient deficiencies, water stress, or pathogenic infections, which may impair photosynthesis and overall plant health.

Wilting in Conium maculatum often results from water stress, root damage, or vascular diseases, leading to reduced turgor pressure and potential plant death.

Leaf spots on Conium maculatum are often caused by fungal or bacterial pathogens, leading to tissue necrosis, reduced photosynthetic capacity, and potential defoliation.

Rotting, particularly root or stem rot, in Conium maculatum is typically caused by fungal pathogens or excessive moisture, compromising structural integrity and nutrient uptake.

Toxicity Warning

Cats
Highly Toxic

Cats are extremely sensitive to the toxins in Conium maculatum. Even small amounts can cause severe neurological and muscular effects, leading to respiratory failure and death. The plant poses a significant risk to feline health.

⚠️ Symptoms:
lethargy tremors muscle twitching paralysis difficulty breathing seizures collapse
🌿 Toxic Parts:
seeds fruits leaves roots
⚡ Toxic If:

if eaten

Prevent cats from accessing any part of the plant. If ingestion is suspected, contact a veterinarian without delay. Hemlock is highly toxic to cats, and prompt treatment is essential for survival.
Dogs
Highly Toxic

Dogs are highly susceptible to the neurotoxins in Conium maculatum. Ingestion causes rapid onset of neurological and muscular symptoms, leading to respiratory paralysis and death if untreated. The toxins act similarly in dogs as in humans, with lethal potential.

⚠️ Symptoms:
vomiting tremors weakness paralysis difficulty breathing collapse dilated pupils
🌿 Toxic Parts:
seeds fruits leaves roots
⚡ Toxic If:

if eaten

Keep dogs away from all parts of the plant. If ingestion is suspected, seek veterinary care immediately. Hemlock is lethal to dogs, and time is critical in treatment.
Humans
Highly Toxic

Conium maculatum, commonly known as hemlock, contains potent neurotoxins, primarily coniine, which disrupt the central nervous system by inhibiting acetylcholine receptors. Ingestion leads to progressive muscle paralysis, respiratory failure, and potentially death. The effects are systemic and can be fatal even in small quantities.

⚠️ Symptoms:
numbness tremors muscle weakness paralysis respiratory failure dilated pupils slurred speech coma
🌿 Toxic Parts:
seeds fruits leaves roots
⚡ Toxic If:

if eaten

Strictly avoid ingestion. Hemlock is a deadly poison with no known antidote. Immediate medical attention is required if exposure occurs. Do not grow near areas accessible to humans or animals.
Important: Keep this plant out of reach of children and pets. If ingestion occurs, contact poison control or veterinary services immediately.

Frequently Asked Questions

Q: Is Poison Hemlock edible?

A: No, all parts of Poison Hemlock are highly toxic and should not be ingested.

Q: How can Poison Hemlock be identified?

A: It has purple spots on the stem, finely divided leaves resembling parsley, and small white flowers in umbrella-shaped clusters.

Q: What are the symptoms of Poison Hemlock poisoning?

A: Symptoms include nausea, muscle paralysis, respiratory failure, and in severe cases, death.

Quick Reference
Family: Apiaceae
Care: expert only
Light: full sun to partial shade
Water: every 7–10 days, allowing so
Suitable For: ["collectors/enthusiasts","wildlife supporters (attracts bees, butterflies, birds)"]
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