Preston Borough Council gardener Tony Lewis, who won best in category for a "Zulu" garden, said despite £2,000 funding from the RHS he does not know whether the council will be able to return in 2016.
Lewis explained that he and his colleagues built the Tatton Park show garden in their own time without charging for overtime and recycled many of the props from previous exhibits, including the fur on the spears from an old Shaun the Sheep design.
It is a "sign of the times" that only Birmingham and Dumfries were at the show, where a decade ago almost 30 councils had plots, he added.
The "Zulu" garden commemorated the Rev George Smith, a chaplain in the Battle of Rorke's Drift depicted in the 1964 film Zulu, who is buried in Preston. Lewis said the garden is "good for Preston and raises the profile of the parks department".