Bosses at the world-famous company said that it was a particularly special occasion for them this year, and that David Austin would have been proud of the milestone award.
The Secret Garden themed display features a fluid, circular design, which houses two new roses - Rosa Eustacia Vye and Rosa Gabriel Oak. The two flowers were named after characters from Thomas Hardy's works.
David Austin, managing director of the Albrighton-based company and David Austin Senior's son, said the awards was testament to decades of hard work.
"Chelsea is always a very special occasion for us and this year it is particularly so, as the first since my father’s passing," he said.
"I’m sure 'Mr A' would have been both humbled by and proud of this significant achievement - our 25th gold medal. The award really is testament to the decades of hard work and dedication that have gone into creating the very best roses.
"It is also wonderful acknowledgment of these exquisite plants and a true reflection of their on-going popularity in all their variations.”
Famous faces including Mary Berry, Joanna Lumley and David Walliams visited David Austin Roses on the press day.
The Royal Horticultural Society, which hosts the prestigious festival, had also invited David Austin Roses to install a floral memorial at this year's show.
Mr Austin died at his home in Albrighton in December last year, at the age of 92.
Hundreds of messages were sent from across the world in tribute to the rose breeder.
He was credited with developing what is now known as the English Rose, and bred more than 240 different breeds during his 75-year career.
The Chelsea Flower Show opens to the public today.
Yesterday saw visits to the flower show by The Queen, Prince William and Duchess of Cambridge, Kate Middleton.
Last year David Austin Roses received a number of celebrity guests, including Mary Berry and David Walliams.