The time has come to get things ready for winter. It seems that the weather has been reluctant to cool down, but for me it seems like that every year! I love working in the garden in the fall once the temperatures and the humidity start to fall. It is not unusual to get a few spring-like days here and there in the middle of winter. Here in the Charlotte area, the soil doesn't freeze, at least not the way it does in colder zones (think Asheville, Boone, and Hendersonville), but there are still things that can and should be done to prepare gardens to weather the winter months.
There are many diseases that can overwinter around plants, lingering in the leaves and detritus underneath them. Roses and camellias are particularly susceptible, but many other flowers and shrubs have the same problem. This is an excellent time to do a little clean-up. Rake up the leaves and debris under the plant, including the top layer (at least) of mulch and dispose of it. If you know that a plant had a disease (Black spot on roses comes to mind), don't put the debris in a compost pile--they get hot, but rarely get hot enough to destroy fungal spores. It is best to bag it and put it at the curb.
There are about as many different opinions on fallen leaves as there are yards to clean, but they basically fall into two categories--to rake or not to rake. Raking is great exercise and the piles are fun for kids and animals to jump in. Leaves on lawns shade out the grass and can cause both bare spots and the spread of fungal diseases the next summer. Leaves in the flower beds can likewise lead to problems with both diseases and insects, as the eggs and dormant adults secret themselves in them. If leaves are left in the beds or used in the compost heaps, they are better used when mulched. This can be accomplished in one of two ways: 1. get a leaf mulcher (an electric one runs about $200 and can be easily purchase online), or 2. run the leaves over with a bagging mower and collect the mulched debris. The mulching breaks up the larger surface area and discourages slimy masses of wet leaves growing things in the landscape.
Fertilizer should have been applied already, in around July and August. Except for winterizing lawn fertilizer, most fertilizers include nitrogen and even a relatively small amount can trigger new growth that will be damaged by frost and cold and can potentially damage the plant for spring growth.
If you have irrigation, have a good irrigation company winterize it for you, but be aware that plants need water even when dormant in the winter. Most established plants can tolerate a relatively dry winter, but newer plantings will need applications of water from time to time if rain is scarce. Make some plans to provide water at least once a week if it doesn't rain.
Finally, after the majority of the leaves have fallen, it is a good idea to apply some fresh mulch. It can add a layer of insulation against the freezing weather we often get here. Since snow is hit or miss, mulch can help protect the root system from dry cold which can be much more damaging. Roses, rosemary, sages/salvias, and other somewhat tender perennials can often be nursed through an extra cold spell with heavy mulch and a cold blanket. NEVER use plastic to cover plants against frost--it conducts cold and provides little or no protection. Old sheets or garden cold covers are much better.