Looking like this when you buy one, Pernettya is a small evergreen shrub, with slightly prickly leaves, grown primarily for its tremendous show of large berries.
It is an Ericaceous plant, which is to say that it hates Alkaline or Lime rich soils. Once established it will reach 60cms averagely in height, and forms thickets of groundcover.
Probably the plant capable of producing the greatest number of large shinny berries that you’ll ever come across.