Thoughts of winter care for the gardens are on minds everywhere. What is done in gardens around the country vary as much as the color and size of roses do.
How much time you want to spend and what you want to accomplish are a determining factor. Some things to consider now is checking the pH, it is a good time to lime if needed as the rainy weather will help the lime become absorbed into the soil. pH is the measure of acidity or alkalinity of the soil on a scale of 0-14. 0 - 6.9 being acid, 7.0 neutral and 7.1 - 14 being alkaline. Heavy clay is more acid and adding organic soil amendments can lower the pH even more. Roses like a slightly acidic soil of 6.0 - 6.5. Dolomite lime is the preferred type if you have a magnesium shortage in your soils, because it provides calcium and magnesium both of which are essential for plant growth.
If you use Epson Salts (magnesium sulfate) then regular garden lime is better. To much magnesium can cause problems with the uptake of other essential elements. If you already feed your roses a balanced fertilizer containing magnesium then you probably do not need to add any Epson Salts to your soil. Only a soil test will tell for sure.
Deadheading now is a good time to prevent botrytis. If you dead head pretty severely now you will reduce the height of the bush and get rid of excess rose canes. Cutting them back to about waist high will help to prevent the wind and rain rocking the rose and creating a problem of opening up an area around the roots. The opening can extend below the ground and may allow freezing temperatures to easily reach the underground parts of the rose. You don't need to bother about the cuts as you would in the spring, when you doing a fine prune.
The same conditions that favor roses also favor diseases and pests. Frequent rainfall and high humidity encourage several leaf diseases. Mild winters allow pests and diseases to live through the coldest part of the year and warm summers give them the chance to build up their populations to survive yet another winter. A year-round approach to pest control will help you manage all of these problems.
Black spot usually occurs on the lower portion of the rose bush first and moves up the plant as the season progresses. Leaves infected with black spot produce the hormone ethylene. High ethylene content in the leaves causes leaf drop. As a result, rose plants infected with black spot lose their leaves and look bare. The dropped leaves around the base of the plant serve as a reservoir of fungal spores which re-infect the plant when it rains or water splashes up. The fungus over-winters on living or dead tissue such as leaves and stems that were infected the previous growing season. Spores will not survive in the soil, so cleaning up the ground is a good practice.
Rust is also a foliar disease that begins in the spring and peaks in early summer. The lesions are small, rusty orange on the top surface of the leaf and can affect the stem as well. Later in the season different spores are produced, they are dark brown with dark thick walls that help them survive the winter.
Powdery mildew is another disease that is present caused when dry days are followed by nights with high humidity. The first infections are on new growth which arises from the previous year's infections.
Aphids can live through the winter in protected nooks and crannies on the plant.
So you are not giving disease and pests a place to reside for the winter, keep the ground and plant, healthy now. A little work now will prevent a lot of work next season.