Using straw for mulch can bring pesky mice
Many recommendations call for straw for mulch. Use it with caution around plants (including roses) that are susceptible to mice girdling the stems. The grain in the straw often attracts the rodents and after they set up housekeeping, they feed on the bark.
In our area, it is not necessary to apply a fungicide to protect the plants during the winter. If your roses were badly affected with powdery mildew, cut off the damaged twigs and clean up the damaged leaves. Discard these to reduce the inoculum that will spread the disease next spring.
As long as you can buy sod, you can still lay it if your soil is properly prepared. Unless it is going to rain or snow right after you lay it, water it well after you install it.