My first impression was that the light yellow background and light blue lettering was a bit pale, that maybe something a bit brighter would be cheerier .. but keeping it clean and simple like it is works just fine too. I don't like a lot of clutter to cause distraction on the homepage of a website but I know from what the Whitinger's created with DG and Cubits that their logo's/banner's will never be cluttered. I think someone mentioned and showed a drawing of a vine and little flower's for the banner and logo which would be perfect! Oh, and I agree with whoever suggested a Butterfly ... gotta include a butterfly!
Did someone suggest changing the logo using just the letters ATP (I thought I saw that suggestion somewhere?) When I first heard about All Things Plants over on cubits, the person posting referred to it as ATP, so I went searching for ATP.com ... and found a website for Aircraft Technical Publishers.