Cold weather greatly reduces plants hydration needs, but it surely does not eliminate them. Lack of rain and snowfall in the winter months can be fatal to trees, shrubs and perennials. Winter plant loss is more often caused by lack of water than by freezing temperatures.
In other words, it’s fine to slow down – but not stop – watering your garden.
Regular winter watering is especially important to recent transplants. I planted several Yuletide camellias in my garden a few summers ago, and with regular watering throughout the year I am now rewarded with splendid flowers.
Snowfall isn’t a concern here but too much or too little rain in the winter months does as much or more harm than the actual cold temperatures. If we do not have rain you want to water weekly in the winter. If we do have rain more than weekly keep an eye on those bulbs. Many tropical bulbs will turn to mush if we get too much rain in the winter.