Caterpillars munch on a variety of plants, mostly those with a mustardy flavour such as:
Adults take nectar from a range of flowers including:
Green-veined Whites spend the winter as chrysalises, usually attached to plant stem and low to the ground, though occasionally stuck to a tree trunk or a fence.
There is even more about this species on the main Butterfly Conservation website
After mating, male Green-veined Whites release a pheromone (scent) onto the female which makes her less attractive to other males.