The Olympic Park landscape is to be managed in its entirety by the Landscape Group as part of a multi-million pound deal.
The 10-year contract worth £6m a year is for estates and facilities management under a joint venture led by Balfour Beatty Workplace.
The Landscape Group will manage the park and tackle biodiversity, all aspects of horticulture and cleaning.
Extra staff for grounds upkeep will be supplied by Groundwork London and social enterprise group Renaisi.
The 10-year deal covers the Olympic Games and the transition of the site to the Queen Elizabeth Olympic Park.
There are no details on staff needs for the job, but the park is the size of 357 football pitches and includes sculpted landforms, thousands of trees, wild flower meadows, 500,000 wetland plants and at least 8km of waterways.
Part of the overall budget will be for running venues and attractions such as handball arenas and the ArcelorMittal Orbit. Balfour Beatty Workplace will manage these venues.
Earlier this week, prime minister David Cameron said: "I want the message to go out loud and clear that we are determined to maximise the benefits of 2012 for the whole country."
The Olympic Park Legacy Company added: "Employment, training and sport opportunities were at the heart of the contracts, along with ensuring venues were affordable, accessible and fit into the wider offer of the future Queen Elizabeth Olympic Park."
357 - Number of football pitches it would take to cover the site of the Olympic Park