Take a close look at the leaves of this Aconitum. See those fine hairs? That's what earned it the common name of downy wolfbane. This tough native of the Caucasus sends up dramatic two-foot long spikes of bloom - either a clear medium blue or light yellow. And it doesn't really care whether your soil is sand or clay, acid or alkaline, as long as it's evenly moist.

 Aconitums are commonly known as monkshood, because the upper
sepal of each flower resembles the hoods of medieval monks. They
attract a variety of butterflies and moths, 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.