Monkshood
Aconitum
Also comes in white.
Monkshood blooms from August through September.
Mature size, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not.
Growing Monkshood
Plant it in part sun. It prefers moderate water. It is hardy in USDA zones 3–7. Expect it to reach about 3.9 ft tall and 1.3 ft wide at maturity, in roughly 3 years.
When to plant Monkshood
Plant Monkshood in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. For the middle of its hardy zones 3 to 7 range, spring means April to June and fall means August or September. Once settled, it blooms from August to September.
Month-by-month timing for your zone is on the planting calendar: for the middle of its range, start with zone 5 in April.
Good to know about Monkshood
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
One of the most poisonous garden plants. Every part holds aconitine, with roots and seeds worst; toxic to people, dogs and cats, and can be fatal if eaten. per NC State
Worth knowing
The same aconitine that makes it dangerous is why deer and rabbits leave it untouched: browsers will not eat it. per NC State
Divide or leave it?
NC State lists division as a way to propagate it, but Illinois calls it hard to move. It resents disturbance, so leave it undisturbed. per NC State and Illinois
Always wear gloves
The toxins soak through skin, worse through cuts, so NC State says wear gloves. Take extra care with the roots and seeds, the most toxic parts. per NC State and Forensic Sciences Research
Keep it from vegetables
NC State warns against planting it near the vegetable garden: the fleshy roots can be mistaken for an edible root like Jerusalem artichoke or horseradish, a documented fatal mistake. per NC State
Dislikes heat
A cool-climate plant that struggles in hot summers. In the South, give it afternoon or dappled shade and keep the roots cool and moist, or it may not last. per Arkansas
Wolfsbane, queen of poisons
Also called wolfsbane and 'queen of poisons' for its toxicity. It was once used to poison wolves and to tip arrows and harpoons. per NC State
What pairs well with Monkshood
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
Creeping Sedum
Takes full sun to part sun and low to moderate water; opens in early summer and overlaps into this one's season; low at 4 in, to carpet the ground beneath; evergreen, so the bed keeps its shape through winter.
Rock Cress
Takes full sun to part sun and low to moderate water; blooms in mid spring, before this one opens; low at 4 in, to carpet the ground beneath; evergreen, so the bed keeps its shape through winter.
Thyme
Takes full sun to part sun and low to moderate water; blooms in late spring, before this one opens; low at 6 in, to carpet the ground beneath; both offer pollinator forage, in different months.
Sea Thrift
Takes full sun to part sun and low to moderate water; blooms in mid spring, before this one opens; lower at 8 in, for the front of the border; evergreen, so the bed keeps its shape through winter.
Sweet Alyssum
Takes full sun to part sun and moderate water; overlaps, then carries the display into mid fall; low at 5 in, to carpet the ground beneath; both offer pollinator forage.
Lavender
Takes full sun to part sun and low to moderate water; opens in early summer and overlaps into this one's season; evergreen, so the bed keeps its shape through winter; both offer pollinator forage.
Lobelia
Shares part sun and moderate water; lower at 8 in, for the front of the border; opens in late spring and overlaps into this one's season; both offer pollinator forage.
Pansy
Shares part sun and moderate water; blooms in early spring, before this one opens; lower at 8 in, for the front of the border; both offer pollinator forage, in different months.
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