From the National Gardening Association:
“During a thaw, checked the garden for heaved plants. Newly planted or shallow rooted perennials are especially susceptible to being heaved out of the ground as a result of the alternate thawing and freezing of the soil, exposing roots to injury from cold and drying. (When there is a thick, insulating blanket of snow, the ground stays consistently frozen, making heaving less likely.) Take a tour of your garden and if you notice heaved plants, push their crowns back gently into the ground.”
Hostas can heave; during my first few years of gardening, I pulled them out. If you plant something new or are just starting out, don’t pull anything until you know for sure what it is. Waiting for a few weeks will give you more information as to what is growing.