Highdown Gardens, an international treasure, has been cared for by the local authority for 50 years today.
Worthing Borough Council marked the milestone with a gathering to launch a new bench in the Millennium Garden.
It was pointed out that it is extremely rare for a garden of such importance to be under council control.
It was on February 19, 1968, that Lady Sybil Stern handed over the gardens on the wishes of her husband, Sir Frederick Stern.
They bought Highdown Towers, high up on Highdown Hill, in 1909 and worked together to prove plants could grow on chalk, creating what is believed to be the world’s first chalk garden.
Sir Frederick sponsored plant hunting expeditions to China and the Far East to bring back exotic plants, which thrived on the chalk and are still there today.
Worthing mayor Alex Harman said: "Highdown is a very special place to come, whether to enjoy a day out in nature or visiting to explore Stern’s impressive ability to grow in seemingly impossible conditions.
"It is testament to the amazing efforts of the Highdown team to stay true to Stern’s growing techniques since Sir Frederick's widow, Lady Sybil, handed over the gardens to the people of Worthing.”
Sir Frederick died in 1967, having stipulated that the council should look after the gardens, using his famous book A Chalk Garden as a reference. Since then, a succession of head gardeners, including John Bassendale, Ron Read, Chris Beardsley, Jo Hooper and Gary Prescod, and their staff have been dedicated to keeping his legacy alive.
An army of volunteers from Friends of Highdown help in the gardens and ensure they continue to win plaudits from gardening experts and visitors around the world.
In December, the council was awarded a Heritage Lottery Fund grant of almost £100,000 to explore ways of preserving and enhancing the gardens further.
A new visitor centre is planned and an archivist and plant expert will be employed to help tell the remarkable story of the gardens and record the stunning variety of plants thriving in the grounds.
Diane Guest, executive member for the environment, said: "Every visit to the gardens fills me with pride and gratitude to those who work hard to maintain Sir Frederick’s vision. It’s a true gem and without the passion of the Highdown team and the volunteers the integrity of Stern’s legacy would be lost.”
The Millennium Garden is currently undergoing a facelift as part of wider plans to preserve Highdown’s future.
Hard landscaping has begun, with hardwood bark chips being laid around the newly-created island beds, a prime site to welcome a botanical style herb garden in the spring.
Interim head gardener Gary Prescod said: "I envision the air being fragrant with the sun-baked oils of lavender, rosemary, pinks, and fennel. A delicious place to sit and dream of the Mediterranean, before dropping down to the coast for a dip in the English channel.”
In a busy year for the gardens, several of its rare plant specimens have been selected as valuable additions to Kew's Millennium Seed Bank at Wakehurst Place.