What exactly do you want it to do for you? LD software is really just a graphics tool - it doesn't actually "design" :-)) Unless you already have a working knowledge and understanding of landscape design elements/processes any LD software is no better than just using graph paper and pencil.

But if you just want to chart out what you already have, any of the Paint applications, SmartDraw or Google Sketch Up will work fine.

btw, the Landscape Design forum would probably be a better location for this request but be prepared to receive similar advice :-) It's a topic that comes up routinely there.

i found that visiting tour gardens.. and arboretums.. was far better than playing around on my computer ...

ken