Pendant lamps hang from three meters of hessian cord with a plug at one end. You can hang these lamps from a hook in the ceiling , or over a branch  if you wish for versitality..... they can be taken into the garden but are not wired for outside use in the rain!!
You can also  get your electrician to wire them directly into your ceiling rose. I have a multi ceiling rose with three hanging wrapped over a branch to seperate them, which looks lovely!