Perennial · Ranunculaceae family
monkshood
Aconitum napellus
In short a 10-second read
Monkshood (perennial) grows to 0.8–1.5 m tall and 0.3–0.5 m wide when mature. It grows best in full sun to part shade, in average to moist soil. It flowers in July–August; the flowers are blue or purple. Hardy to −32 °C.
× spread 0.3–0.5 m
Where to plant
Sun, soil, frost.
It grows best in full sun to part shade, in average to moist soil. Hardy to −32 °C.
Sun
Tolerates several positions — choose to suit the rest of the garden.
Soil and water
average to moist · watering: moderate
Soil: loamy, humus-rich
Frost
It copes with a normal winter outdoors.
How much space it takes
Mature size.
The mature plant next to a person (175 cm).
Next to a person
Reaches maturity in about 2–5 years. The final size depends on the cultivar and the spot — we give the range from smallest to largest.
Calendar
What to do and when.
Months for Central Europe. The line shows the current month.
The year at a glance
Flowers
July–August · blue or purple
Pruning
No pruning needed — just remove dead or damaged parts.
Planting
container plant: March–May, September–November
Winter protection
not needed
Overwintering
It copes with winter on its own.
It overwinters outdoors without protection, hardy to −32 °C.
- Needs no protection
- Hardy to −32 °C
- Dies back in winter and regrows in spring
What to combine it with
Same needs, different flowering.
They share the same sun and soil and flower in other months — so the bed flowers for longer.
Frequently asked
Quick answers.
When does monkshood flower?
In July–August; the flowers are blue or purple.
Does monkshood tolerate shade?
It tolerates part shade (3–6 hours of sun), but not full shade.
How much space does monkshood need?
At maturity 0.3–0.5 m wide and 0.8–1.5 m tall; recommended spacing 41 cm.
Does monkshood survive winter outdoors?
Yes, without protection, hardy to −32 °C.
Toxicity
Where the data comes from
We compared the data in 14 expert sources. Last checked 18 October 2026.
Show sources (14)
- NC State Extension Gardener Plant Toolbox
- Plants For A Future
- National Capital Poison Center — Monkshood
- ŠOP SR — invázne nepôvodné druhy rastlín vzbudzujúce obavy Únie
- AOPK ČR — invazní rostliny
- Bamberger Staudengarten (Strobler), katalóg
- Foerster-Stauden, katalóg
- Gärtnerei Strickler, katalóg
- RHS - Aconitum napellus
- Iowa State Extension - How to Plant Perennials
- RHS - How to grow perennial plants
- Tox Info Suisse — Giftige Garten- und Wildpflanzen
- BfR / GIZ — Liste giftiger Pflanzenarten
- Giftzentrale Bonn (GIZ Bonn)
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