Hop

About the plant

The hop is one of the few plants grown for a single sex. The female flowers ripen into papery green cones, and at the base of each scale sit yellow glands full of lupulin, a sticky resin whose acids give beer its bitterness and, more usefully to a medieval brewer, keep it from going sour. Monks in ninth-century Germany were the first to put hops in ale; the Dutch brought hopped beer to England in the fifteenth century, to the disgust of ale drinkers, and by Tudor times the hop gardens of Kent were a landscape of poles and bines, picked each September by families from London.

It is a vigorous perennial climber that dies to a crown each winter and in spring sends up shoots that can grow a hand's breadth in a day, twining clockwise, always clockwise, up strings and wires. In Belgium the young shoots are eaten like asparagus. Köhler's atlas included it as a medicine: hop pillows for sleeplessness and a bitter tonic for the digestion, and the plate shows the cones, the lupulin glands and the male flowers in dissection.