Mrs. BD and I, and some friends, have been spending a fair amount of time over recent weeks with a well-known Scottish landscape architect (Scotland born and bred, now working in the US - a legal immigrant!).
We all happen to be responsible for some lands which demand top-notch design and maintenance, and walking around with this fellow discussing design and plant selection - from trees to perennial beds - is a joyful education.
Mind you, we all have a fair and probably well above-average foundation in these things (eg we know what a Little Lamb Hydrangea is, and the difference between an Iris and a Siberian Iris), but a real Landscape Architect (as opposed to a Landscape Designer or, for the bottom of the barrel, a landscaper) not only knows which of the dozen varieties of Boxwoods you need for a spot, but can also step back and produce a big-picture, coherent plan which is more than any of us amateur gardeners could dream of.
Landscape Architects are professionals, and rightly so. A wonderful career. Good people to know.