The genus Aconitum contains 100 species although this is a species that has very few hybrids. The common name is Monkshood because the flowers have a hood that is reminiscent of those on the robes worn by monks.
All parts of these plants are poisonous so it is a good idea to wear gloves when handling them. Another common name is Wolfsbane as the poisonous sap was used to bait wolves.
Aconitum carmichaelii grows in zones 3-8 and blooms in the fall. It has blue flowers that are tightly packed on tall upright spires, like delphiniums, and the plant itself grows 3 feet tall. It becomes a focal point in the garden and the wonderful blue blooms contrast well with the fall foliage of nearby trees and shrubs.
It is native to Russia and Northern China and other temperate regions of the world and is long lived and pest free. It does best in areas where the summer nights are not too hot. All aconites have palmate leaves with lobes.
The leaves of the fall blooming aconites are especially striking and the foliage of Aconitum carmichaeli ‘Arendsii' are thick like those of a succulent and each leaf is beautifully veined. It likes morning sun and afternoon shade in the north and filtered shade in southern gardens.
Propagate by division once the leaves have died back in the fall. Aconitum napellus is happy in moist woodland gardens, grows to 4 feet and has purple/ blue flowers in zones 5-9.Aconitum ‘Ivorine' is a hybrid with pale flowers and ‘vulparia' is a species with hairy leaves and pale yellow blooms.
If you have the tiny winter aconites in your garden that start off the progression of flowers each spring, you may wish to plant the larger fall blooming aconites which are one of the last flowers to bloom in the fall. Then aconites will be like bookends in your flower garden.