coming late to the question, I know, but thought I'd chime in anyway. :-D
Interestingly I thought I'd google landscape architects and it would appear that it is a fairly common term.
Given that the definitions tend to be #1 about the design of buildings and #4 (way down the list) about more general design, I do believe that the landscape architects are playing on a combination of the first definition and the fourth and counting on the populace to make the connection. Sooooo, really the term architecture can certainly be used in reference to landscaping, but it means something a bit different....like someone being the chief architect for peace in the middle east. That's architecture too, right? But the meaning is
drawn from the first definition, it's not really the same as the first. *blush* ok. I'm done.
Lond-winded for a question answered a few days ago, really, I know. Hehe-- I dig semantics though.
![Smile :)](./images/smilies/icon_smile.gif)