Did you do any easter themed marketing this year? How about hosting a neighborhood easter egg hunt for the local kids? Maybe give away some prizes too?
Maybe hold it at a local park?
Have an easter bunny costume and take free pictures of the kids with the easter bunny and have them uploaded to your site for the family to download.
Maybe have baskets of candy to the first x amount of kids that show up?
Create a flyer that you could distribute with all the promotional information about the event on one side and maybe promote your lawn care service on the other side? You could put this on a door hanger too.
Could you also do this with the church you are involved with?
Could you print out the pictures of the child on the easter bunny's lap and attach it to a magnetic backing? Then maybe put your logo and phone number at the bottom? Easter 2009 - John's lawn care 555-0822
Then when the family shows up at your event, take their address and tell them you will send them a free fridge magnet with their child on it.
By doing this, you will then build up your marketing mailing list where you can send them future promotional literature.