Scope out your neighborhood and observe which residents hire a commercial lawn care company to maintain their yard. A legitimate company should have a company name, logo and phone number on the side of its trucks. Ask neighbors about the costs and whether they know other customers who use the same service. Contact every person noted, ask them how much they pay for lawn care service, and inquire as to how they heard about the company and why they selected that company over other lawn care providers.
Visit the clerks at your local town hall, county office building and school district. Tell them you want to see contracts, proposals and invoices from landscaping companies that they do business with. Even though government entities do much of their lawn care work in house, they might contract a potion of that work out when their highway, grounds or public works employees are tied up on other projects. If companies bid on a public contract, they may be required to note rates and list other customers and/or annual revenues. Sales tax records are also subject to public records laws. According to the Federation of Tax Administrators, Alaska, Montana and Oregon are the only state where sales tax on personal or business services is not charged.
Ask representatives from the lawn care companies to disclose information about their accounts. They are not legally required to do so and may decline your request. If you show, however, that you've done some research on them already and say you still need to learn more about their success or lack of it to decide whether you would hire them (or whether you would go into the lawn care business yourself, which you wouldn't want to tell them), they might be willing to be forthcoming with account information.