I'd almost be interested but with no traffic details or current revenue there's not enough information to make an informed decision.
The site itself has plenty of good content but it's coded badly and isn't particularly well designed - after buying it you'd have to redesign and add in a CMS to make it work - then find some good affiliates to sell through to increase revenue.
Perhaps a partnership rather than outright buyout? That way you get the obvious gardening knowledge base of "riverbirch" added to the extra marketing and
SEO knowledge of a web professional combining to create a site that could become a large and informative gardening community.
If you integrate with Joomla or Drupal, add in a forum and get a database feed from a good gardening supplier you've got a lot of potential.