I like it. I like the idea of the $20 off for referrals. Did you put a limit on it at all? What if someone gives you a butt load of referrals, but they are only $20 jobs. Just make sure you're making money and not giving too much away. As for the flyer's appearance, I give it an A
I'd think twice about the $20 per referral as said before.
Also I would use Aerating instead of spike aeration ( is there another kind?)
maybe Mulch/Straw Installation Fertilization Weed Control
Also maybe lose the Basic Services and just list your services.
Not trying to be overly critical.
Hope that helps!