Career as a Landscape Architect
I am a landscape designer. You can not technically be a landscape architect until you have a BLA or MLA from an accredited university, have two years working for a registered landscape architect and pass a national exam (which is the part I can't seem to finish, ugh.)
There are many different ways to go in the field of landscape design. You can pursue anything from residential design to working on large urban and municipal projects. I think the latter to be more ''garden design'' and is often miscalled landscape architecture. A landscape architect deals much less with perennial planting and garden bed layout, and more with things like EIR's, site grading and drainage, paving, programming for large scale site uses, etc. Almost all of their work is on Autocad and coordinated with Architects, Civil Engineers, Structural Engineers, etc. I'm not implying one is better than the other, I think they are both wonderful things to pursue, it's just that from my experience they are two completely different things and depending on what interests you it should inform how you want to be trained.
If you want to pursue garden design then I'd go to Merit College. They have an extension course that I think is well suited for this. If you want to pursue landscape architecture and you are really serious about it, then I'd look into UC- Berkeley's program. I don't think it's that good compared to a lot of the programs on the east coast, but it is close, and inexpensive.
As for salary. It again depends on how you choose to practice. I think the starting salary here for somebody with a MLA from a good school (Berkeley, Harvard, University of Pennsylvania or University of Virginia) would earn anywhere from $35,000 - $45,000. I don't know about garden design. San Francisco has I believe the most landscape architecture firms of anywhere in the country, so it is a GREAT place to be. There are some of the world's best firms here, and there are many wonderful smaller firms which do wonderful design. You will work ALOT. It is not one of those leave at 5 kind of jobs. It is a work at nights, work on weekends, love what you do passions. Underpaid and overworked. I don't know one landscape architect who isn't slightly bitter about this situation.
I'd go to Builder's Bookstore or Stout's in SF and just look at the books. See if you can identify with any of it and that will probably tell you where you want to go. Good Luck.
still trying to pass the exam