Content Detail

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 monk’s cape, thus the common name. All parts of this plant are poisonous, especially the bulbous roots, and should be planted with caution, especially near vegetable gardens and where children play.

  • Family (English) Buttercup
  • Family (botanic) Ranuculaceae
  • Tree or plant type Perennial
  • Native locale Non-native
  • 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 (Northern Illinois), Zone 6 (City of Chicago), Zone 7
  • Soil preference Moist, well-drained soil
  • Tolerances Occasional flooding
  • Season of interest early fall, late summer, midsummer
  • Flower color and fragrance Blue, Purple
  • Shape or form Upright
  • Growth rate Slow
  • Wildlife Game mammals


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

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 inches 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, whereas Delphinium has 4.

Fruit description:


  • All parts of this plant are poisonous, especially the roots, so wear gloves and take precautions 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.


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