The Walled Garden, at Wynyard Hall Hotel, Tees Valley, which opened earlier this month, has met the criteria laid down by VisitEngland under the Visitor Attraction Quality Scheme.
Containing more than 3000 roses, the £1.6m development to the north of the Hall also features a state-of-the-art visitor centre, shop and café, stocking and serving locally-sourced goods and produce.
All were praised in the VisitEngland assessor's report, which highlighted, "the extremely impressive and very well maintained grounds" and "the very high presentational and cleanliness standards."
The report singled out the "exceptional" shop and retail staff working within the visitor centre.
"The range of merchandise on offer was extensive," it continued, and, "the shop was a joy to visit."
Allison Antonopoulos, Managing Director at Wynyard Hall Hotel, said: "We are delighted to have achieved Quality Assured Visitor Attraction status from VisitEngland.
"The assessor's feedback was very much appreciated and in line with the lovely comments visitors have made since we opened."
The Walled Garden is the second stage in a rolling programme of work to create The Gardens at Wynyard Hall – which will eventually cover four acres and be one of the largest rose gardens in the UK.
The first stage, adjacent to the Walled Garden, was the £1.7m installation of a Grand Marquee and management suite, for weddings and large scale corporate events and further stages will include a £2m investment in the creation of a cookery school, children's garden and designated walks through the estate.
The Gardens and Visitor Centre are open daily between 10am and 5.30pm and tickets for the garden cost £5 for adults, £2 for children aged between 5 and 12, £14 for a family pass for two adults and three children and £30 for an annual pass for up to eight visits a year.