Owner and garden designer Alison Pao said: "I have always loved Peter Beales Roses, so it was an honour when the grower chose us to be its first South East outlet.
"Beales does not have many garden centre outlets and they are just the type of roses that will prove very popular with our customers."
Peter Beales Roses managing director Richard Beales said: "Garden centres such as Rowan are a perfect outlet for our roses. Everyone there knows their plants and gives superb advice and it is a real plant lovers' garden centre so they should do very well with our classic roses."
The nursery was set up in 1972 by Peter Beales, who has received a lifetime achievement award from the Garden Media Guild. Its classic roses have won it 18 gold medals at RHS Chelsea Flower Shows, as well as the president's award for best exhibition.