Its brown stem is thought to resemble a snake skin and the seeds like a viper's head therefore it was prescibed as an antidote to Viper's bites! Beautiful tall pink/blue flowers appear on 4ft spikes in second year, loved by insects. One of our favourite herbs. 
Type: Hardy Biennial 
Height: 1m+
Spread: 40cm 
Soil type: Will tolerate most soil types 
Aspect: Sun/light shade 
Flower colour: Blue/pink 
Flowering time: Summer