HERBACEOUS PERENNIAL VINES 93 
to its culture: try to give it too much manure, 
and you will obtain some of the finest tubers you 
ever laid eyes on. That is all this plant requires 
to be grown well—manure and plenty of it. 
Though grossly neglected, one of the best her- 
baceous climbers, and a vine that can be used for 
screens, hedges, and any place where a dense 
foliage is required, is the hop (Humulus lupulus) 
This is a splendid screen plant. Being a twiner, 
it clings well and attains a height of thirty feet. 
The flowers are produced in panicles similar to 
those of the annual hop, but after the flowers are 
gone the plant is still attractive, with its curious 
little papery, straw-coloured vessels which are 
the hops of commerce. 
When grown commercially on a large scale, 
hops are trained on poles, the same as Lima 
beans. But instead of about an inch of the side 
branches being left on the poles they are removed 
altogether, the poles being left perfectly smooth. 
The plants are trained to these poles, and, when 
the crop is ready to be harvested, are cut at the 
ground and the pole pulled up. It is then an easy 
matter to pull the pole away, leaving the vines 
to be thrown into a wagon and carted off. 
A yellow variety of hop which fits in wher- 
ever this colour is wanted is the yellow-leaved 
