I think Halloween is a great time to be doing outdoor decorations. One of the things you could do this season is really decorate your own property and front door. Then stick a Halloween decoration yard sign in your front lawn along with many other yards in your area. It would be really quick and easy to do and a great way to get the word out about your outdoor Halloween decoration business.
In fact why not have a community decoration contest? That would get a lot more people involved. Take pictures of homes in your area and post them on your lawn care business website. Then on Halloween, choose a winner and present the homeowner with some kind of award.