Get a FREE subscription to LASN (Landscape Architecture and Specifier News) at http://www.landscapeonline.com.
It is an advertiser supported magazaine more focused on the day-to-day practice of LA. They have excellent features of everyday projects (not just the famous and flashy (and lately foreign) ones LAM focuses on) and they keep on top of codes and technology. The great thing about ad supported is that there is, of course, lots of advertising and new product announcements. One of their self-proclaimed highlights are the number of new product announcements every month. Every spring, they publish a product guide which takes a place of honor on my desk, filled with small post-it notes flagging products to look into. From there, you can go to the manufacturers websites for CAD/BIM and for specs.
There is also a product section on http://www.landscapeonline.com which is helpful, but a bit disorganized, and the manufacturers don’t always have links, just names.