Wear home made clothes or ridiculous psychadelic tie die clothes, clothes of natural materials. They tend not to wash very often, hence they look like they have just slept in a hedge, or in fact live in hedges although we all know they really live in a squat with a peace symbol painted on the front door.
Somebody who tends to live the 'hippy' way of life to the extreme, they usually have white-boy dreads & take lots of 'earthy' drugs (weed/mushrooms/psychoactive plants etc & lsd), love travelling to festivals / acid techno squat parties in their 'freedom wagons' or VW camper vans, Beetle's or 20 year old decomissioned old service vans/trucks etc. Usually vegetarians and love going on protest marches/anti war/anti fox hunting marches etc.
Can be heavily into spirituality & regularly smell of josticks or special brew / cider. Sometimes mistaken for tramps.
"Last year at Glastonbury a hedge monkey was trying to sell me a 2nd class stamp saying that it was a giant tab of acid."