You're welcome. Adding content is always a good idea. <img src="/images/icons/smile.gif" alt="" />
I do want to make it clear that I'm not going to review your site, so any advice from me may or may not be helpful. You could start discussions among yourself and your closest friends (who might have computers). After all, if I go to a discussion site, and I don't see any discussion (not even a single message from the people running the site), I would assume that no one is there, and I wouldn't bother posting. As a result, an ODP listing, or listings in all the search engines of the world might not help if there's nothing on the site.
The successful discussion lists in the areas with which I am most familiar (not necessarily high-tech, either) generally started either from informational pages (where someone published articles on a subject, and then decided a discussion would be useful), or from existing communities (either online or offline groups/clubs/circles-of-friends). You'll probably do a lot better drumming up support by contacting other landscape enthusiasts (but please, no spamming), rather than waiting for them to come because they saw your site in a search engine or directory.