Carmichael’s monkshood

Carmichael’s monkshood: how do you recognise it?

Habit

Upright clump, 1.2 m tall and 50 cm wide, with stiff, leafy stems.

Leaves

Leathery, glossy dark green, deeply lobed like a hand and toothed.

Flower

Spikes of helmet-shaped flowers in deep violet-blue, in September and October.

Roots

Fleshy, tuberous roots, the most poisonous part of the plant.

Toxicity

All parts are highly poisonous, even through contact with the sap.

Flowering: September–October · Plants: March–April and September–October · Pruning: March and November

Why grow it?

• One of the last perennials to flower: deep blue in September and October.
• Bumblebees love the flowers and still find food here late in the season.
• Grows in part shade too, where few other autumn flowers bloom so well.
• A fine cut flower for autumn arrangements; always cut it wearing gloves.
• Very hardy and long-lived: it rarely needs dividing.

Carmichael’s monkshood: where does it grow best?

• Sun or part shade; full sun only if the soil stays moist.
• Fertile, moisture-retentive loam or clay, acid to chalky.
• Moist to wet, but not standing water; drought gives brown leaf edges.
• Plant 50 cm apart, in the middle or back of the border.
• Not next to the vegetable garden, a play area or a field with horses or cattle.

Light

Sun and partial shade

Soil type

Loam or clay

Acidity

Not fussy

Moisture

Normal or wet

Size

1.2 m tall, 0.5 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Michaelmas daisy: Purple and pink flowers next to the deep blue, in the same months.
• Japanese anemone: White or pink flowers at the same time, also in part shade.
• Bugbane: White, scented spikes in autumn, in the same moist soil.
• Ornamental grasses: Airy plumes as a contrast to the stiff stems.

Carmichael’s monkshood: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or in September–October, when the ground is not frozen.
2. Dig a hole twice as wide as the root ball and mix in compost.
3. Set the plant at the same depth as in its pot, with the buds just below the surface.
4. Leave 50 cm between plants.
5. Water well and spread a layer of leaf mould around the base.
6. Wear gloves when planting and wash your hands afterwards.

Care

Water

Keep the soil moist; in dry summers water generously every week.

Feeding

Compost or an organic fertiliser in spring.

Mulching

A layer of leaf mould in April keeps the roots cool and moist.

Support

‘Arendsii’ usually stands firm; taller forms need support in a windy spot.

Leave alone

Let it grow undisturbed: an old clump flowers best.

Tip: Put it in the middle or at the back of the border, out of reach of children and pets: that way you can enjoy its late, deep blue flowers without risk.

Carmichael’s monkshood: when to prune it?

Pruning months: March and November.

When: After flowering, in November, or in March, before the new shoots appear.

How:

• Cut the faded stems back to 10 cm above the ground.
• In March remove the dead leaves and clear everything away.
• Put the prunings in the green waste bin, never in a field or near animals.

Caution: Wear gloves and long sleeves: the poisonous sap can be absorbed through the skin.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March or October: lift the clump, split it into pieces each with a few tuberous roots and buds, and replant straight away. Always wear gloves.

Carmichael’s monkshood: how does it get through the winter?

Hardy to −35 °C.

• Very hardy, to about −35 °C: no protection is needed in Belgium.
• The stems die back after flowering; the plant reshoots in March–April.
• In a pot: stand it in a sheltered spot against a wall and keep the compost slightly moist.

Diseases and pests

• Brown leaf edges: A sign of drought or too much sun. Water generously and mulch the soil.
• Flopping stems: In a windy spot or on soil that is too rich. Give support.
• Powdery mildew: White powder on the leaves at the end of dry summers. Water at the base and cut off affected leaves.
• Root rot: The stems wilt in standing water. Choose soil that stays moist but drains.

Through the year

• March: Clear old stems. Plant or divide. Add compost.
• April: Plant. Mulch.
• May: Support tall forms.
• June: Water in dry spells.
• July: Water in dry spells. The stems grow taller.
• August: Water generously. The flower buds appear.
• September: Flowering begins. Cut flowers wearing gloves.
• October: Full bloom. Plant or divide.
• November: Cut off the faded stems.
• December: Rest.

Edible and useful

Not edible. Monkshood is one of the most poisonous plants in Europe: all parts, especially the root, contain aconitine, which can even be absorbed through the skin. Always wear gloves when cutting back, dividing or picking the flowers, wash your hands afterwards and do not plant it where children play. Never eat it, not as a herb nor as a tea. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The striking helmet is not a petal but a sepal; the true petals have become nectaries hidden under the hood.
• Mainly long-tongued bumblebees can reach the nectar under the helmet.
• The cultivar ‘Arendsii’ is named after the German nurseryman Georg Arends.