Here is another place you can get free templates. http://www.oswd.org/
They have over 2000 to chose from.
I never worried too much about looking for a landscaping theme but there are lots available. I tended to look more for colors and layout that I liked and changing a photo or so turns it into a landscaping theme.
Wordpress and Dreamweaver. I have never used Wordpress but I have heard good comments about it. I started off long ago using FrontPage which was easy to use then switched to Dreamweaver. Dreamweaver has a bit more of a learning curve but it's an excellent program.