However, Leith Penny - who becomes strategic director for city management at the local authority following implementation of its structural changes on 1 October - told HW that those managing the contract need not necessarily have a horticultural background.
"I believe Westminster council can continue to provide a class-leading parks service without the person managing the contract having a horticultural background," he said. "But there does need to be horticultural expertise in the team."
The local authority is undergoing a restructuring exercise that will enable it to employ a model called "strategic commissioning", which replaces traditional departments with a series of delivery units and support units (HW, 14 August).
A total of 500 vulnerability letters have been sent to staff across the London authority and around 200 people will go, with a further 70 posts already vacant.
In the parks team, five of the six managers currently employed will keep their jobs at the council.
But those retained managers may not continue to work with the open spaces contract, which is held by Continental Landscapes.
"It is possible that someone who started with a grounds maintenance management background ends up working on, for example, a cleansing contract," added Penny.
The aim of the exercise, according to Penny, is to strip the council of any "silo" mentality and ensure there is no repetition of generic skills in different departments.
Around £10m in savings is ex-pected to result from the changes.
"We realise the future is financially grim for everyone in the public sector," he said. "If we can find more cost-effective ways of achieving a particular objective, why wouldn't we?"
Next year could be a good time for Westminster's existing open space strategy - produced in February 2007 - to be reviewed, and an opportunity to test the efficacy of the new regime, Penny added.