Winter Fern Conium maculatum
Other Common Name(s):
- Phonetic Spelling
- KOH-nee-um mak-yoo-LAY-tum
- This plant has high severity poison characteristics.
- See below
- Description
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Poison hemlock is an erect biennial weed in the Apiaceae (carrot) family. It is found growing in disturbed areas, roadsides, along fences streambanks, or in ditches.
It starts growing emerging from the soil with a basal rosette of fine-textured ferny leaves in early spring, while it is usually a biennial growing for 2 years, in ideal locations it can be perennial. Reaching a mature height of 6 to 9 feet tall poison hemlock grows in full sun to partial shade and moist soils. It reproduces by seeds are dispersed by animals, machinery, and clothing and persist in the soil profile years making eradication difficult.
It has a white fleshy taproot with red spots that resembles a parsnip and hollow stems with small purple spots. Showy white flowers look like umbrellas or like other members of the carrot family. The leaves of poison hemlock resemble parlsey's leaves (Petroselinum crispum). The roots, leaves, and stems have a foul odor when crushed.
Insects, Diseases, and Other Plant Problems: This plant is extremely poisonous to both humans and livestock. Wear gloves when handling.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- Tags:
- Cultivars / Varieties:
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- Tags:
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Attributes:
- Genus:
- Conium
- Species:
- maculatum
- Family:
- Apiaceae
- Life Cycle:
- Biennial
- Perennial
- Country Or Region Of Origin:
- Europe, Mediterranean
- Distribution:
- Naturalized in USA
- Dimensions:
- Height: 6 ft. 0 in. - 10 ft. 0 in.
- Width: 4 ft. 0 in. - 5 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Herbaceous Perennial
- Perennial
- Poisonous
- Weed
- Habit/Form:
- Erect
- Growth Rate:
- Rapid
- Maintenance:
- High
- Texture:
- Fine
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Drainage:
- Moist
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Fruit:
- Fruit Color:
- Brown/Copper
- Gray/Silver
- Green
- Fruit Description:
- Green ovoid to suborbicular compressed laterally and wavy ribbing on the surface containing several seeds. At maturity fruit turns gray-brown. The seeds resemble anise.
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Flowers:
- Flower Color:
- Pink
- White
- Flower Inflorescence:
- Umbel
- Flower Value To Gardener:
- Showy
- Flower Bloom Time:
- Summer
- Flower Petals:
- 4-5 petals/rays
- Flower Size:
- < 1 inch
- Flower Description:
- Small, white 5 petaled, in terminal umbrella-like clusters with one purple flower in the center of the cluster. Flowers appear late summer.
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Leaves:
- Leaf Color:
- Green
- Leaf Type:
- Compound (Pinnately , Bipinnately, Palmately)
- Leaf Shape:
- Deltoid
- Ovate
- Hairs Present:
- No
- Leaf Description:
- Large, 3-4 pinnately dissected, the leaflets broadly ovate to deltate very delicate and resemble parsley leaves with prominate veins on the underside. They clasp the stems at enlarged nodes.
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Stem:
- Stem Color:
- Brown/Copper
- Green
- Purple/Lavender
- Red/Burgundy
- Stem Is Aromatic:
- No
- Stem Buds:
- Smooth/Hairless
- Stem Cross Section:
- Round
- Stem Surface:
- Smooth (glabrous)
- Stem Description:
- Smooth, purple, brown, or red spots and fine regular lines, hollow stem foul odor when crushed.
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Landscape:
- Problems:
- Contact Dermatitis
- Malodorous
- Poisonous to Humans
- Problem for Cats
- Problem for Dogs
- Problem for Horses
- Weedy
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Poisonous to Humans:
- Poison Severity:
- High
- Poison Symptoms:
- HIGHLY TOXIC, MAY BE FATAL IF EATEN! Delivery by ingestion. Salivation, vomiting, diarrhea, muscular weakness, paralysis, nervousness, trembling, dilation of pupils, weak pulse, convulsions, coma.
- Poison Toxic Principle:
- Alkaloids coniine and others
- Causes Contact Dermatitis:
- Yes
- Poison Part:
- Bark
- Flowers
- Fruits
- Leaves
- Roots
- Sap/Juice
- Seeds
- Stems
