Found a highly toxic plant on my walk today in a neighborhood down the street from me! Poison hemlock (Conium maculatum).

Poison hemlock is a highly toxic, invasive plant in the carrot family. It grows throughout much of the United States, including Virginia, and is commonly found along roadsides, creek banks, fence lines, vacant lots, and disturbed soil. It is native to Europe, Africa, and Asia.

Key identification features

• Tall growth: Often 5–10 feet tall.

• Purple-blotched stems: Smooth, hollow green stems with irregular purple spots or streaks are one of the best identifiers.

• Fern-like leaves: Finely divided, lacy leaves that resemble parsley, carrot tops, or wild chervil.

• White umbrella-shaped flowers: Flat-topped clusters called umbels bloom in late spring to early summer.

• Strong odor: Crushed leaves often smell unpleasant or “mouse-like.”

Extremely important safety note

All parts of the plant are poisonous!

• Leaves
• Roots
• Stems
• Leaves
• Seeds
• Flowers

It contains toxic alkaloids that can cause:

• Nausea
• Tremors
• Paralysis
• Respiratory failure

Even handling it can irritate skin in some people, and accidental ingestion is a medical emergency for humans, livestock, and pets.

Common lookalikes

Poison hemlock is often confused with:

• Queen Anne’s lace (aka Wild carrot)

Queen Anne’s lace (Daucus carota) is a common, hardy biennial wildflower and the wild ancestor of the domestic carrot. It is highly prized by foragers and gardeners for its edible taproot (when young) and pollinator-friendly blooms, but it is also easily confused with highly toxic lookalikes. 

Key Identification Features

• Stems: Solid, green, and covered in fine hairs. (Remember the saying: “the Queen has hairy legs.”)
• Flowers: Dense, flat-topped clusters of tiny white flowers. Often, there is a single, dark purple or black “blood” drop flower in the very center.
• Under-flower bracts: Lacy, leaf-like structures (bracts) sit directly beneath the flower cluster.
• Aroma: When crushed, the leaves and stems smell distinctly like carrots.
• Seed head: As it goes to seed, the flower cluster curls inward to form a bowl resembling a “bird’s nest”

• Cow parsley

A common, tall, white-flowered plant in the carrot family (Apiaceae) found across Europe, western Asia, and northwestern Africa. Often seen in hedgerows and woodlands from spring to early summer.  Also known as wild chervil, it’s recognized by its feathery leaves and clusters of small white flowers, but it is crucial to distinguish it from poisonous look-alikes like hemlock, as it can be confused with toxic species. While young leaves are edible and have a mild flavor, the plant is also used ornamentally and is being researched for potential medicinal compounds. 

Identification

• Flowers: Small, white, in umbrella-like clusters (umbels).
• Leaves: Feathery and fern-like, similar to parsley.
• Stems: Hollow, ribbed, and often hairy.
• Height: Can grow quite tall, often 1-2 meters. 

• Wild chervil

Cow parsley (Anthriscus sylvestris) is a common tall, white-flowered plant in the carrot family found in Europe, western Asia, and northwestern Africa, often seen in hedgerows and woodlands from spring to early summer. Also known as wild chervil, it’s recognized by its feathery leaves and clusters of small white flowers, but it is crucial to distinguish it from poisonous look-alikes like hemlock, as it can be confused with toxic species. While young leaves are edible and have a mild flavor, the plant is also used ornamentally and is being researched for potential medicinal compounds. 

Identification

• Flowers: Small, white, in umbrella-like clusters (umbels).
• Leaves: Feathery and fern-like, similar to parsley.
• Stems: Hollow, ribbed, and often hairy.
• Height: Can grow quite tall, often 1-2 meters. 

A major clue is the smooth purple-spotted stem. Wild carrot/Queen Anne’s lace usually has:

• Hairy stems

• Smaller stature

• No purple blotching

Removal

If removing it:

• Wear gloves, long sleeves, eye protection
• Avoid using weed trimmers or mowers that aerosolize sap/plant particles
• Bag plants securely
• Wash clothing afterward

• Young plants are easiest to remove before flowering and seed production.