My back neighbors did the no mow May in thing in their back yard. They had used a lawn service for a few years so it was very well fertilized with few dandelions...

They ended up having to rent a walk behind weed whacker to tame it. She was out a few days raking. I don't know what they did with the all hay but yesterday I noticed it's finally looking like an actual lawn again.

He apologized a while back about all the unsightliness of it all. I told him it wasn't a problem for me at all and I was actually curious to see how it went. He's like well, (our other neighbor) had more dandelions then we did and it broke my mower so we're not doing it again next year.