I first started using alfalfa as a organic supplement for roses, but I long ago discovered that almost everything loves it. Living in Chicago, I don't have access to a Tractor Supply and often don't feel like driving far away from the city to find one, but I am lucky to have a local feed store (catering to chicken and beekeeping supplies since both are incredibly popular around these parts) that will special order alfalfa meal and alfalfa pellets whenever I need them. I don't remember the brand, but I get 50 lb bags of pure alfalfa with no additives.
Unless I am digging a new bed, I just top dress with alfalfa and then water it in well. I don't have any problems with critters eating it or being attracted by it (knock on wood). Aside from its nutritional content, I find one of the main benefits is that it attracts and encourages earthworms. Even if spread over compacted soil, there will soon be enough earthworms to loosen it nicely and they will leave castings to help the plants thrive.
I don't have many mature clumps of day lilies yet, but my huge Hemerocallis citrina Yao Ming (a form sold by Plant Delights) had scapes over 5 feet tall this summer and stayed in bloom for over two months. I only use alfalfa and very occasional doses of Neptune's harvest fish and seaweed fertilizer on all of my garden plants.
