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Poison Hemlock Conium maculatum

Other plants called Poison Hemlock:

Phonetic Spelling
KOH-nee-um mak-yoo-LAY-tum
This plant has high severity poison characteristics.
See below
Description

Poison hemlock is a biennial, herbaceous weed in the carrot family (Apiaceae). It is native to Europe and the Mediterranean but has naturalized in the United States and become problematic. It is highly toxic and can be fatal to people and livestock. Many states have listed it as a noxious weed. 

It grows 6 to 10 feet tall and 4 to 5 feet wide and quickly colonizes an area and displaces native plant species. Its white fleshy taproot has red spots and resembles a parsnip or carrot. The stems are hollow and have small purple spots. Showy white flowers look like umbrellas or like other members of the carrot family. The leaves of poison hemlock resemble parsley. The roots, leaves and stems have a foul odor when crushed.

It is found growing in disturbed areas, at roadsides, along fences, on streambanks or in ditches. In early spring it emerges from the soil with a basal rosette of fine-textured ferny leaves. While it is usually a biennial, in ideal locations – full sun to partial shade and moist soils – it can be perennial. It reproduces by seeds which are dispersed by animals, machinery and clothing and persist in the soil for years, making eradication difficult.

Insects, Diseases and Other Plant Problems: No significant problems.

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#showy flowers#poisonous#white flowers#pink flowers#fine texture#lacy leaves#high maintenance#moist soil#fast growing#disturbed areas#malodorous#problem for cats#problem for dogs#problem for horses#roadside#contact dermatitis#weed
 
Cultivars / Varieties:
Tags:
#showy flowers#poisonous#white flowers#pink flowers#fine texture#lacy leaves#high maintenance#moist soil#fast growing#disturbed areas#malodorous#problem for cats#problem for dogs#problem for horses#roadside#contact dermatitis#weed
  • 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.
  • Whole Plant Traits:
    Plant Type:
    Herbaceous Perennial
    Perennial
    Poisonous
    Weed
    Habit/Form:
    Erect
    Growth Rate:
    Rapid
    Maintenance:
    High
    Texture:
    Fine
  • 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
  • Fruit:
    Fruit Color:
    Brown/Copper
    Gray/Silver
    Green
    Fruit Description:
    Green ovoid to suborbicular compressed laterally and wavy ribbing on the surface. Each fruit contains a single seed, and the fruits are generally called "seeds." At maturity, fruits turn gray-brown. The fruits ("seeds") resemble those of anise.
  • 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.
  • 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.
  • 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.
  • Landscape:
    Problems:
    Contact Dermatitis
    Malodorous
    Poisonous to Humans
    Problem for Cats
    Problem for Dogs
    Problem for Horses
    Weedy
  • 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. People with highly sensitive skin may experience contact dermatitis from handling this plant.
    Poison Toxic Principle:
    Alkaloids coniine and others
    Causes Contact Dermatitis:
    Yes
    Poison Part:
    Bark
    Flowers
    Fruits
    Leaves
    Roots
    Sap/Juice
    Seeds
    Stems