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Flowers of monkshood.

Monkshood is an upright, 2 to 4 foot high perennial with lovely blue-violet, spiked flowers that appear in mid-to-late summer. The distinctive, helmet-shaped flowers resembling the hood of a monks cape, thus the common name. All parts of this plant is poisonous, especially the bulbous roots, and should be planted with caution, especially near vegetable gardens and where children play.

Botanical name:

Aconitum napellus

All Common Names:

Monkshood, Helmet flower, Wolfsbane

Family (English):


Family (Botanic):


Tree or Plant Type:

  • Perennial

Native Locale:

  • Non-native

Landscape Uses:

  • Mixed border,
  • Patio/sidewalk

Size Range:

  • Large plant (more than 24 inches),
  • Medium plant (12-24 inches)

Light Exposure:

  • Partial sun/shade (4-6 hrs light daily)

Hardiness Zones:

  • Zone 3,
  • Zone 4,
  • Zone 5 (Chicago),
  • Zone 6,
  • Zone 7

Soil Preference:

  • Moist, well-drained soil


  • Occasional flooding

Season of Interest:

  • Mid summer,
  • Late summer,
  • Early fall

Flower Color & Fragrance:

  • Blue,
  • Purple

Shape or Form:

  • Upright

Growth Rate:

  • Slow

More Information:


An upright, erect perennial reaching 2 to 4 feet high and 1 to 2 feet wide

Plant Care

All parts of plant is poisonous, especially the roots, so wear gloves and taken precaution when working with this plant.
Best in part shade in a moist, rich organic soil. If planted in sun, maintain soil moisture to avoid scorch. Water in dry periods.
Best left undisturbed, slow to recover from division. Plants prefer cooler growing conditions and will not tolerate hot summer temperatures.
Deadhead flowers to promote secondary growth. Cut back foliage in spring to promote bushier growth.
Staking may be necessary to control height.

Disease, pests, and problems

Mites, powdery mildew, verticillium wilt, and crown rot in wet soils.

Disease, pest, and problem resistance

Deer and rabbits

Native geographic location and habitat

Found in moist pastures and mountain areas in Central and Western Europe and Asia.

Leaf description

Alternate, dark green, 3 to 5 inch wide, palmately-shaped and divided at base.

Flower description

Upright, terminal spikes, violet-blue with enlarged upper sepal, resembling  the hood of a monk's cape.
Flowers appear in mid-to-late summer.
Flowers similar to Delphinium but Monkshood has 2 petals and Delphinium has 4.

Fruit description


Location of Aconitum napellus (Monkshood) at the Arboretum

We do not seem to have this in our living collection.