Very fast to load. You've done a good job in optimising your graphics. A fast loading front page is absolutely essential. Very much like that you haven't just concentrated on selling but have provided info such as Plant Care and a Picture Gallery. Good for visitors coming back.
Navigation is pretty much spot on.
Easy to find all the bits of the site and very easy to get from one sub-page to another without going via the home page again. I see you use MS FrontPage. I have to say this is one of the best FP produced sites I've seen as FP does tend to produce a lot of useless HTML tags and be somewhat IE specific in its use of the tags. Your site is great and the pictures are beautiful. I'm located in Northern NH and have a very short growing season.