Chemlawn Corp. met an unexpected suitor.

Oak Brook, Ill.-based Waste Management Inc. made an unexpected offer to buy Columbus, Ohio-based Chemlawn for $270 million. The move would expand Waste Management’s residential services business from trash hauling into lawn spraying. Stephen Hardymon, Chemlawn’s manager of legislative affairs, said the offer, which appeared in newspaper advertisements Thursday, came as a surprise to the company. He said Chemlawn had not talked previously with Waste Management and had not been a takeover target of other companies.