Are there different kinds of geraniums such as annual and perennial? What is the difference between seed geraniums and the other kind? Can I winter seed geraniums?

Yes, there are annual geraniums (correctly known as pelargoniums) and perennial geraniums. There are a number of different species of perennial geraniums, they are mostly used for foreground, mounding growth habits type plants for the front of borders, or for rock gardens. There's a wide variation in foliage types, and flowers too. I grow one called 'Johnson's Blue' which is only about eight inches tall and produces blue flowers all summer.

There are two main types of annual geraniums, seed and zonal. Seed geraniums are from seed, are smaller plants and have smaller clusters of blooms, but they are quite free-flowering and well-suited for mass plantings in flower beds. Zonal geraniums are propagated from cuttings, are larger plants and have bigger blooms. You can overwinter these indoors, you cannot overwinter seed geraniums.