Aconitum napellus brings tall, dense spires of violet-blue hooded flowers to cool, moist borders in midsummer.
Its upright clumps carry deeply divided, toothed dark green leaves. Plant in partial shade in deep, humus-rich soil that stays moist but drains well, then add compost and mulch to conserve moisture.
All parts are extremely toxic to people and animals, and skin contact is hazardous, so wear protective gloves whenever handling the plant.