Last year on Twitter I came across the people behind Confluent Forms. They're a webdesign and development firm that is doing some incredible things with Blogger. Confluent Forms is making some really cool websites using Blogger and really showcasing the power of this content management system. They're also developing some neat templates for Blogger that you may want to look into.
Their Sartorial line of templates is really creative and they showcase photography well. They developed Sartorial2 and Sartorial3 with food bloggers in mind to showcase pictures of food. But I think they would work just as well as garden blog templates if you're looking for a template to set your garden blog apart. The difference between Sartorial 2 & 3 is the number of columns the templates have. Sartorial 2 has two columns, while Sartorial 3 sports three columns.
What's really cool is that they've designed these templates so that you can still use Blogger's template designer to customize them even further.
Visit both of the templates and click around to see them in action. You can download the templates from here.
Update: I have installed the Sartorial3 template at the MrBrownThumb garden blog. One thing I should note is that if you have posts with images that are justified to the left or right side of the column, you should edit your posts and center them, or they'll get pushed way down on the page.