Aconitum barbatum
Also known as: Monk's Hood · Slenderleaf Monkshood
Deadly poisonous
When & where
Germination
Spacing & depth
How to plant
Surface-sow seed onto moist seed-starting mix and press in gently — light aids germination. Cold-stratify in the fridge 4–6 weeks, or sow outdoors in fall. Transplant seedlings 12–18 in apart in rich, moist soil.
Grower's tip
All parts are highly toxic if ingested. Wear gloves when handling. Tall spires of hooded blue-violet flowers; excellent back-of-border perennial in shade gardens.
Good to know before you grow this
Parts of this plant are toxic to people and pets — don't eat it and keep it away from children and animals.
Soil preferences
Well-drained garden soil. Native/wildflower species prefer lean soil; cutting flowers prefer richer beds.
6.0–7.0
Work 1 in of compost into beds before sowing. Skip nitrogen fertilizer on wildflowers — it favors foliage over blooms.
Watering
1 in per week during establishment, drought-tolerant once rooted for most species.
Deep, infrequent soakings at the base. Overhead water on ornamentals promotes botrytis and rust.
Overwatered: rotted crowns, mildew, floppy stems. Underwatered: small blooms, curled leaves, quick fade.
Either works — Bottom-water seed trays and young potted annuals to protect fragile stems from damping-off. Top-water established plants at the base in the morning so foliage dries by night. Avoid overhead sprinkling on open blooms.
Temperature tolerance
60–80°F (16–27°C) ideal for most annuals
50–65°F (10–18°C)
Cool-season annuals (larkspur, poppy, snapdragon) tolerate light frost; warm-season annuals (zinnia, cosmos, marigold) are frost-tender.
Container growing
Possible with the right cultivar
8–14 in (20–35 cm) wide
Compact and dwarf types do best in pots; tall cutting flowers need staking.
Detailed harvesting
Nothing here is harvested for the kitchen. Wear gloves for any cutting or deadheading, keep the sap off your skin and eyes, and wash your hands and tools afterwards.
Post-harvest storage & preservation
Do not dry, store or preserve any part of this plant near food. Bag prunings for the bin — never compost them where animals browse, and never burn them.
Culinary, medicinal & other uses
Ornamental only — this plant is poisonous and has no food, tea or home-remedy use. Grow it for looks, wear gloves, and keep it away from children, pets and livestock.
Medicinal or traditional uses are shared for interest only — this is not medical advice. Consult a qualified professional before using any plant medicinally.
Seed saving
Mostly insect-pollinated (outcrossing).
For pure strains, isolate 150–800 ft or bag heads. Wildflower mixes are meant to cross freely.
Stop deadheading favorite blooms; let heads dry brown and rattling on the stem, then collect into a paper bag.
Your zone's planting calendar
Pick your USDA hardiness zone and we'll estimate the key dates for aconitum barbatum in your area. These are regional averages — always check your own last-frost forecast before sowing.
My Aconitum barbatum notes
Aconitum barbatum seeds on hand
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