it's smart to offer a bread basket of services. people like one stop shopping, I'd suggest contacting a licensed pest operator (small guy) & a sprinkler co, and talk to them about combining services with you & you can offer complete packages.
Also, include landscape installations, mulch, turf, etc. They are great add ons. There is plenty of literature available for landscape design and remember each region has different design elements and preferences. For example, down here people love mountains of colorful impatiens this time of year, especially along the beach, other areas tend to prefer a more subdued landscape.
Everybody here will have an opinion and what's best, but your market is localized so take what you need here, take the rest with a grain of salt & leave the criticisms's altogether.
By the way, don't wait for the phone to ring, it won't. Go out and meet people, go to church? join the men's group, tell everybody what you do, don't be shy about telling them you could use the business. People love to help. The more people know you, the more they are likely to do business with you.
Don't quit before the miracle!