The long and the short of it. Two rows of Jerusalem Artichoke (Hellianthus tuberosous) on the allotment. To the left one of the usual varieties that grow to about 10ft/3m tall. I don't know which variety exactly, I bought a bagful at a farmers market early last year to plant rather than eat. There were about 20 tubers in the bag which had multiplied to around 200 when I harvested them a year later. Some got eaten the rest I replanted. 

 To the right a shorter variety that grows to about 4ft/1.2m in height. I am trying these for the first time. I was looking for 'Dwarf Sunray' which permaculturalists in America seem to be very keen on. Hard to find in the UK but I came across a variety called 'Stampede'. The Norwegian website 'Edimenetals' is a very useful resource and the author speculates that 'Sunray' and 'Stampede' are one and the same. Indeed go by other names as well, for example 'Bianka' in Russia.

 H. tuberosous is a relative of the Sunflower (H. annuus) and is topped by bright yellow flowers in autumn- if it flowers. They seem to be shy to flower in UK but Stampede/Sunray flowers a month or so earlier which might help.

 A very low maintenance perennial vegetable. Plant the tubers, leave them to it. They stay in the ground till harvesting in late winter/early spring as and when you want to eat some. I haven't fed or watered them, they outgrow any weeds apart from Bindweed which I snipped at the base and left to wither on the stems. I'm expecting quite a crop!