While it won't be cold enough in the Smoky Mountains to make pipes freeze up tonight, it will be cold enough in the Smokies to damage some plants in your gardens by freezing tender new buds and shoots.
The first thing to do to protect your plant is bring inside any sensitive flowering plants that you can. Too many plants to bring inside or the pots are too large to move them around? You can lay them on their side and cover the plants with a cloth.
If you are covering plants make sure to not cover them with plastic unless it can not touch the plants as plastic touching plants that freezes will cause more damage. You can separate the plastic cover on your plants with cloth. Though it probably won't be brutally cold tonight in the Smokies to have to worry about this, sometimes it is best to cover cloth that is over plants with a layer of plastic to block the wind.
Pine needle mulch and leaf mulch both work great to protect plants against freezing - just be sure to remove it the next day so the plants warm up.
Another good idea is to make sure the soil is very damp before it gets cold as the damp soil tends to stay warm longer than dry soil. You do not want plants to be wet when the freeze begins as that will cause more intense damage.