Apiaceae
Fool's Parsley (Aethusa cynapium)
Aethusa cynapium
A toxic plant for outdoor management only. Prefers well-draining soil and moderate to full sun. Water moderately once a week, allowing the topsoil to dry slightly between waterings. Propagated only by seed. Extreme care required due to severe toxicity — always use gloves.
Every 7 days
Partial shade
5° - 30°C
40% - 70%
Categories
What is Fool's Parsley?
Fool's Parsley (Aethusa cynapium) is a hard-care plant from the Apiaceae family. Aethusa cynapium, commonly known as Fool's Parsley or Dog Poison, is a highly toxic annual herb in the family Apiaceae, native to Europe, western Asia, and northwest Africa. It closely resembles common parsley but is dangerous — all parts of the plant are poisonous when fresh, containing the alkaloi...
Fool's Parsley grows up to 1.2m, spread of 45cm, watering every 7 days, 5°C – 30°C, 40–70% humidity. It is not suitable for indoor environments and not safe for pets.
Unlike easy-care plants, Fool's Parsley demands constant attention to humidity and light. Not recommended for beginners. Without precautions, ingestion can cause irritation in pets. Keep out of reach of cats and dogs.
How to Care for Fool's Parsley?
TLDR: Fool's Parsley needs Partial shade, watering every 7 days, and temperatures between 5-30°C with 40-70% humidity.
How Often Should You Water Fool's Parsley?
Water weekly, allowing the top layer of soil to dry out between waterings. Avoid waterlogging; excess moisture promotes root rot.
How Much Light Does Fool's Parsley Need?
Tolerates full shade to full sun, but grows best in partial to full sun exposure. Suitable for open garden locations with good natural light.
What Is the Best Soil for Fool's Parsley?
Prefers well-draining loamy soil, slightly acidic to neutral (pH 6.0-7.5). Adapts to sandy and clay soils provided drainage is adequate.
What Is Fool's Parsley and Where Does It Come From?
Aethusa cynapium, commonly known as Fool's Parsley or Dog Poison, is a highly toxic annual herb in the family Apiaceae, native to Europe, western Asia, and northwest Africa. It closely resembles common parsley but is dangerous — all parts of the plant are poisonous when fresh, containing the alkaloid cynopine. It commonly grows as a weed in gardens and cultivated ground.
How to Propagate Fool's Parsley?
Seed
Sow in situ as the plant does not transplant well. Always wear gloves when handling.
- 1 Collect ripe seeds in autumn or purchase certified seeds
- 2 Sow directly in the final location in spring or as soon as seeds are ripe
- 3 Cover lightly with soil and keep moist until germination
- 4 Thin seedlings to 20-30 cm spacing
Materials needed:
How Big Does Fool's Parsley Grow?
TLDR: Fool's Parsley can reach up to 1.2m tall with Medium growth rate.
Max height
1.2m
Spread
45cm
Growth rate
Medium
Foliage
Deciduous
Warning: Toxic Plant
This plant can be toxic if ingested. Keep out of reach of:
Plant Uses
Medicinal
Medicinal properties
Medicinal Uses
- Historically used in European folk medicine to treat gastrointestinal complaints, summer diarrhea in children, and convulsions. Modern medicinal use is strongly discouraged due to severe toxicity.
Is your plant showing symptoms?
Click on the symptom to discover possible causes:
What Diseases Commonly Affect Fool's Parsley?
TLDR: Fool's Parsley is susceptible to 5 known diseases. Monitor regularly for early detection.
Aphids
Aphids are small, soft-bodied, pear-shaped insects (1/16 to 1/8 inch long) that feed by sucking nutrient-rich sap from plants. They reproduce rapidly and can quickly weaken plants, causing distorted growth and transmitting plant viruses. Aphids come in various colors including green, black, red, yellow, brown, and gray. They secrete honeydew, a sticky substance that attracts ants and encourages sooty mold growth.
Caterpillars
Caterpillars are the larval stage of moths and butterflies that feed voraciously on plant foliage, stems, flowers, and fruits. Common species include cabbage loopers, tomato hornworms, armyworms, and cutworms. These pests can cause extensive damage by consuming large amounts of plant tissue in a short time. They vary in size from small (1/4 inch) to large (5 inches), with colors ranging from green to brown, often featuring stripes or spots. Caterpillars are highly mobile and can quickly spread throughout gardens, making them one of the most destructive common pests.
Root Rot
Root rot is a serious fungal disease that affects the root system of plants, causing them to decay and die. It is primarily caused by overwatering, poor drainage, or soil-borne fungi such as Pythium, Phytophthora, Rhizoctonia, and Fusarium. The disease thrives in waterlogged conditions where roots are deprived of oxygen, making them susceptible to fungal infection.
Damping Off
Damping off is a soil-borne fungal disease that affects seeds and young seedlings, causing rotting of stem and root tissues at and below the soil line. It is caused by several fungi including Pythium, Rhizoctonia, Fusarium, and Phytophthora. The disease thrives in cold, wet conditions with poor air circulation.
Fun Facts
It is the only species in the genus Aethusa worldwide
The name Aethusa derives from Greek/Arabic roots meaning burning, referring to the toxin effects
Despite resembling parsley, its unpleasant odor is a key identification feature
The dried plant loses most of its toxicity compared to when fresh
Frequently asked questions
Is Fool's Parsley dangerous?
How do I tell Fool's Parsley apart from common parsley?
When does Fool's Parsley flower?
Is it safe to grow this plant in the garden?
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| Creeping bentgrass | Hard | Direct sun | 3d | ✓ |
| Crystal Anthurium | Hard | Partial shade | 7d | ⚠️ |
| Saguaro | Hard | Direct sun | 21d | ✓ |
| Lisianthus | Hard | Bright indirect | 7d | ✓ |
