The garden, located at Dyffryn Gardens, was restored using the original design by Thomas Mawson and early 1900s photographs.
The project included rebuilding hedges, beds, pathways, and selecting long-lasting, disease-resistant plants.
Chris Flynn, head gardener for south east Wales at National Trust Cymru, said: “We were inspired by Thomas Mawson’s original design of the rose garden.
“Our goal was to blend our existing historical research with innovative horticultural practice and create a garden which will continue to flourish for many years.”
Volunteers played a key role in the restoration, dedicating 407 hours over 10 weeks to prepare and sort 1,146 pieces of stone found in nearby farm fields.
David Austin roses now fill the garden with a vibrant display of colour and fragrance, ranging from fuchsia and blush pink to peach, lemon, and white.
The blooms could continue to bloom into early October and will continue to mature each year.
Lizzie Smith Jones, general manager for south east Wales at National Trust Cymru, said: “Our lives are so busy, and we want Dyffryn Gardens to be a space where people can truly pause, take a breath and reconnect with nature in this breathtaking space.
“Truly stop and smell the roses.”
No advance booking is required, and entry is free for National Trust members.
More information about visiting can be found at www.nationaltrust.org.uk/dyffryn-gardens.
