More than 1,100 people have signed a petition demanding that parking charges are dropped at a tourist attraction.
Wakehurst Place near Ardingly in Sussex announced in April it would charge visitors up to £10 to park, in an attempt to tackle a £1.4m deficit.
About 80% of its visitors are National Trust members and previously benefited from free parking, alongside free entry.
For this the estate receives an annual endowment of £80,000 from trust.
Wakehurst Place is the country estate of the Royal Botanic Gardens, Kew.
A spokeswoman for Wakehurst said: "The decision to introduce parking charges was taken at the highest levels at both the National Trust and the Royal Botanic Gardens, Kew, and was agreed by both organisations' boards of trustees."