Greetings Google Researchers!

I'm interested in starting a garden/landscape design business in
Southern California, and I'm in need of info regarding how to go about
this, and what it is I can legally do as a landscape designer. For the
record, I have studied horticulture and landscape design, but I do not
have a degree.  I would be a landscape DESIGNER, not a landcape
ARCHITECT.

My Questions:

I would like to know what, if any, licences etc. I would need in order
to provide landscape design services.

I would also like to know what my limitations are as a designer, under the law.

Also, I have friends that are garden designers, and it seems that many
of their clients want them to manage the job and hire the contractors,
as well as come up with the design for them.  As such, I would like to
know whether or not there is any way I would be able to legally act as
a manager/overseer on the installation of my designs.  In other words,
could I act on the owner/clients behalf, and hire the licensed
contractors that will be needed to implement/install my design?  And
if so, would I be able to charge for the management of the job, as
well as my design?

Additional Info:

My studio/office would be in my home in Whittier, CA.  I would not see
clients at my studio/office, but would instead go to them.  I would
only work on designs in my studio, and do paperwork.  Also, It is
doubtful that I would have any clients in this city (not many gardens
here!).  I would mostly be travelling to other cities.

I have friends that are garden designers, and it seems that many of
their clients want them to manage the job and hire the contractors, as
well as come up with a design for them.

I hope my question makes sense.  If clarification is needed, please
don't hesitate to email and ask.

Thank you!