A friend recently wrote me to ask:
"My wife and I are thinking about changing around our backyard a bit... She has some grand ideas and wanted to see how this process works. If we wanted to work with you, what are the fees, how do we find a contractor to do the work... you know the usual stuff..."
I recently shared my answers about selection criteria and fees for landscape design. Here, I'll briefly describe how the design process works:
The process itself usually has 5 distinct phases:
1) Discovery - interviewing you, measuring and documenting your site, researching municipal ordinances (e.g. drainage requirements) that can affect the design, etc.
2) Functional Planning - abstractly determining how the various areas of your site should work and interact, e.g. where the BBQ should live relative to the swingset.
3) Preliminary/Schematic Design - giving general form to the functions determined above; this is the color drawing that people drool over. See one example of mine -- notice that the circular deck (lower left) isn't described in any more detail than "Wood Deck"; this is typical generality for this phase. Start talking to contractors now.
4) Final/Construction Plans - the "blueprints" that your site gets built from, including specific plants/locations, hardscape dimensions & finishes, irrigation & lighting recommendations, and other details; for instance, that "Wood Deck" might now be called out as "Redwood 2x4 flooring, countersink screws, stain Mahogany & seal". Contractors develop bids from this. Note that unless your professional is licensed (as an architect or contractor), they are legally prohibited from providing dimensions, grading or drainage specifications, or other construction details.
5) Installation - The contractors' time to shine, but you might still want your designer around in a supporting role, e.g. inspecting and placing plants, checking that the finished work matches up with the intent of the design, making substitutions and judgment calls on the inevitable issues that arise.
The first 4 phases usually take me at least 6-8 weeks, again depending on the complexity of it all. The installation can take weeks or months depending on the contractor. For best prices and availability, start your planning around December and your construction as soon as weather permits. Also, have a firm budget for design and construction, just as you would for buying a home. Don't hire someone to provide a design and then ask "how much will this cost?" You're wasting your money and everyone's time. Current thinking is to spend 5-10% of your home's value on landscaping, for a 1-3x ROI when you sell.