treat them exactly the same as the white ones.

There's only one hardy one - Zantedeschia aethiopica 'Crowboroough'.. All the others need to be taken into a frost-free place for the winter and dried off - then started off again in fresh compost in the spring.

Spritzhenry is right, and I'd imagine you're talking about Zantedeschia cultivars - but you have called the plant arum lily - there IS an Arum lily which is not a Zantedeschia, and its Latin name is Arum - these are hardy outside whether they're coloured or not.