This particular Aconitum, generally known simply as blue Aconiturm,  is one of the last monkshoods to bloom. From late summer into fall, its rich blue color and strong vertical form make it a welcome companion to airy fall anemones and mounding chrysanthemums. Bees and butterflies love it; slugs, rabbits and deer hate it. No wonder it's been a garden favorite since Victorian times.

Aconitums are commonly known as monkshood, because the upper
sepal of each flower resembles the hoods of medieval monks. They
attract a variety of beneficial insects, and are the primary food
source for Old World bees. Another common name, wolfbane, refers to the
poison made
from this plant's roots, which was used to tip hunting arrows.
Medicinal (and poisonous) uses of this plant date back to ancient times.
What's the difference between a medicine and a poison? Dosage.