Heracleum lanatum (H. maximum)

cow parsnip

Habit: grows to be a robust, multi stemmed, erect herbaceous perennial. Hollow stems and leaves are densely hairy. The enormous basal leaves are round to kidney shaped, becoming 7-20 in (20-50 cm) wide, sharply serrated and lobed.  The fragrant, almost flat-topped inflorescence is a large umbel with 15-30 white flowers.  Flower buds appear as conspicuous, large, swollen areas on the stem, sometimes the swellings are as large as an orange. Two seeds are enclosed in a large flat, green, egg-shaped dry fruit with 2 broad wing-like sides.  Seed heads have a parsley-like scent and persist into early winter in the umbel formation.  Blooms early summer to early autumn.

Ecology: found in riparian zones, moist woods, meadows, thickets and disturbed areas up to elevations of 8500 ft (2600 m), native throughout much of North America.

Growing Conditions: full to partial sun in moist soil, low drought tolerance.

The broad flower heads attract many insects, bees, butterflies and/or birds. In some portions of its range it may be considered weedy or invasive.  It is listed as endangered in Kentucky and of special concern in Tennessee.  Heracleum lanatum can cause a very itchy rash similar to poison oak in some people.  The plant contains a phototoxin, furanocoumarin, and can cause a reaction after coming in contact with the plant, followed by exposure to sunlight.  It’s best to plant away from pathways.


Herbaceous Perennial
3-10 ft (1-3 m)
2-4 ft (.5-1.5 m)
USDA Zones:

Native Habitat

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