Does anyone know if winter will kill off the garden plants?

How do you guys maintain your gardens?! I only recently got my sim into it and she had about 8 plants and 2 trees, but it was such a chore to water them every day and tend to them. I dont want to hire a garden professional either because I wanted my sim to take pride in her garden but after 2 days of having to do other things the garden started going downhill.