HI Nancy
I have never heard of it or tried it because by the end of summer my tomato plants are diseased and not worth the effort. I think you are better off starting with new plants each year.

Rhubarb needs little care once established but adequate water is essential. Do not harvest rhubarb in the fall, let the foliage die back to return nutrients for next year. When the plant dies down, mulch with compost but do not cover the center of the plant (crown). It is hardy in the cooler climates and will winter over.
Parsley on the other hand in grown as an annual because it bolts and produces seeds in the spring the second year. If you protect it from the cold during the winter it will still continue to grow but once spring arrives and the weather gets warmer it will bolt.

For the cold winter wait until the plant is dormant and the ground is frozen. Mulch your rose with 12 inches of straw, woods chips and put a rose collar around it and fill with sandy soil/straw or shredded leaves. There is a new rose collar available in garden centers, that is plastic and allows air to circulate. This avoids heat build up on a sunny winter day and prevents freezing and thawing. Remove the collar around April.

I haven’t heard of it or tried it. I don’t see why you couldn’t dehydrate them. You may discover a new taste sensation. Have you tried fried green tomatoes?