Having trouble keeping up with the weeds here too! I use Preen or corn gluten meal in the spring and after each section gets weeded. The smaller gardens are all done by hand. I clean them as I walk by and see a weed. The larger garden is more difficult due to its size and the fact that I am the only one who works in it. I have found a good rototiller to be a great help. It gets used on a regular basis wherever it will fit. I also mulch the edges of the plots of iris heavily and lightly over the rhizomes.
My biggest complaint are the frikkin thistles. Seems like nothing gets rid of them completely .I only use round up on a spotty basis - like for poison ivy.
I hear that there is a special breed of trained chicken that is useful
- but we don't have them here!