American Cow-Parsnip

(Heracleum maximum)

American Cow-Parsnip (Heracleum maximum)

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Estimated Native Range
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Summary

Heracleum maximum, commonly known as American Cow-Parsnip, is a deciduous perennial herb native to moist meadows, forest clearings, and stream banks across North America, extending to the Russian Far East and Japan. It typically grows over 2 m (7 ft) tall, with hollow and densely hairy stems. The large, lobed leaves can reach up to 40 cm (16 in) across, and the plant features characteristic white flower umbels of the Apiaceae family, about 20 cm (8 in) wide, which may have larger outer flowers. Flowering occurs from late spring to midsummer, and the seeds are 8–12 mm (0.3–0.5 in) long and 5–8 mm (0.2–0.3 in) wide. The plant is often mistaken for the invasive Heracleum mantegazzianum (giant hogweed), but lacks the purplish spots on the stems and has less serrated leaves.

American Cow-Parsnip is valued for its architectural presence in the garden, with its large leaves and striking flower umbels that can add a dramatic touch to naturalistic plantings. It is used in restoration projects, especially in riparian zones, and can be found in wildflower gardens. It thrives in full sun to part shade and requires high amounts of water, adapting to a range of soil drainage conditions. While it is not typically prone to diseases, it can become aggressive in some conditions and may require management to prevent unwanted spread. Gardeners should handle with care, as the sap can cause skin irritation in some individuals.CC BY-SA 4.0

Plant Description

  • Plant Type:
  • Height: 4-8 feet
  • Width: 4-6 feet
  • Growth Rate: Moderate
  • Flower Color: White
  • Flowering Season: Summer
  • Leaf Retention: Deciduous

Growth Requirements

  • Sun: Full Sun, Part Shade
  • Water: High
  • Drainage: Fast, Medium, Slow

Common Uses

Bee Garden, Bird Garden, Butterfly Garden, Deer Resistant, Edible*Disclaimer: Easyscape's listed plant edibility is for informational use. Always verify the safety and proper identification of any plant before consumption., Water Garden

Natural Habitat

Moist meadows, forest clearings, and stream banks across North America, extending to the Russian Far East and Japan

Other Names

Common Names: Indian Rhubard , Cow Parsnip , Cowparsnip

Scientific Names: Heracleum maximum , Heracleum lanatum , Heracleum sphondylium subsp. montanum , Heracleum dulce , Heracleum montanum , Heracleum setosum , Heracleum sphondylium var. turugisanense , Heracleum dubium , Heracleum sphondylium var. lanatum , Heracleum ceretanum

GBIF Accepted Name: Heracleum sphondylium subsp. montanum (Schleich. ex Gaudin) Briq.