For my first house, I did what you are doing -- designed my own
garden. It was beautiful but so labor-intensive that I was
gardening by moonlight because there was not enough daylight.

For my second (current) house, I had a professional design my
garden, with strong inputs from me. It looked as nice as the
garden in my first house but required less labor. The designer
worked for a nearby nursery. Because I bought my plant materials
there, the design was free. (I paid for the design and received
scrip for that amount, useable for purchases of materials.)

That was 30 years ago (half my lifetime). Over the years, my
garden began to lack vigor. The cause was the shade from a tree.
When I planted it from a 5 gallon can, the trunk was as thick as my
thumb. It was about 10 feet tall. The garden was designed for
lots of sun.

Now the trunk is almost 3 feet in diameter and towers over my
two-story house. So last year, I had a new garden designed and
installed. (My back is just too old for that much digging.) The
new garden is designed for part-shade throughout. I retired
shortly after the new garden was installed, so I have plenty of
time to putter. But it is a low-effort garden. To read about it,
visit my gardening Web site, per my signature below.

In any case -- whether you install it or have it done -- I strongly
suggest you have professional advice on your garden's design.
Otherwise, you too can become a slave to a landscape.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 19 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a)
Gardening pages at http://www.rossde.com/garden/