I hate to be the bearer of bad tidings, but this winter will have a devastating effect on your garden!
We have had very little snow cover, and the temperatures have yo-yo'd up and down all winter. It's been in the 30's and 40's and then down in the teens and 20's. This is NOT good for your garden!
Snow provides a wonderful insulating layer above the ground, keeping the frost level from going crazy. When the temperature goes up and down like it has this year, it forms frost heaves in the garden as well as on the roads. It's terrible for the root systems and bulbs that are trying to rebuild themselves for another season of growth. They get yanked up and down. Then when the thaw comes and the rain soaks the ground, what's left is a disaster.
Be prepared to deal with a poor showing in the spring. When the thaw comes, get out and try to press roots and shrubs, and even perennials back into the ground. It may be a rebuilding year for the garden!
I looked up "frost lines" on the internet and came across this VERY interesting link about frost in the ground. It doesn't really talk much about plants, but it sure paints a picture of what's going on under the ground up here in New England, and why we have so many stones in our gardens! Give this link a "click"
and spend the time you read thinking, "Wow! Who would have known!" It will give you an entirely new insight into your garden, the ground, and why there are so many stones...and what frost has to do with it!