Jason Allison, landlord at the pub in Main Street, took over the business last year.
He said that the new outside space was due to be ready for Mother's Day, but it had to stay under wraps as the coronavirus pandemic resulted in all pubs in the UK closing at the end of March.
He said: "We started planning it in early January with the intention of having it ready for around Mother's Day so we were able to get a full year's use out of it.
"Obviously Covid-19 had other plans and frustratingly it turned out to be the hottest April and May on record!
"Regardless, we carried on, finished it and hoped for the best."
Jason said he was recommended garden designer, Pétalos Garden Design & Maintenance, which is owned and run by Louise Clague, from Morecambe.
Louise had spent several years living in Valencia, Spain, which has greatly influenced her approach to garden design.
Jason said: "It would have been easy (and much cheaper!) to just plant a few hanging baskets and tidy the garden up, but we wanted to create something special and unique that would really engage our customers and get them talking.
"With Lou's Spanish influences and my love of quirky British quintessential-ism, the garden is a hybrid of English country garden meets rural Spain.
"And with the Royal being a fresh food kitchen delivering seasonal menus every month, I wanted a kitchen garden feel with lots of fresh herbs scattered throughout.
2In one section there are a number of olive trees, Mediterranean herbs, flagged stone floors, lots of rustic timber and large white pebbles covering the beds, giving it the feel of an arid and hot Mediterranean courtyard."
The garden also features a water feature made from a classic roll-top bath with traditional taps, modified with vintage rowing oars to create "a sea-worthy rowing tub".
"I think people thought I was joking when I told them what I had planned," Jason said.
"One of the concepts Lou and I really wanted to drive home, was the idea of upcyling; the creative re-use of old and characterful items that could be transformed into quirky and imaginative planters and pieces around the garden," he said.
"Not only did it give many of these objects that were otherwise destined for the scrap heap a second lease of life, it brought the sort of quirky and unique feel we wanted to achieve.
"Among the items we used and turned into planters there were pianos, vintage suitcases, old pallets turned into wall planters, an old tuba, WW2 air-raid warden helmets, antique watering cans, potato scales, type writers, vintage telephones, butter churns, and a doctor's leather satchel."
Owned by pub company Punch Taverns, which bought the building from Mitchells of Lancaster last year, The Royal is run under a lease arrangement through Jason's company Fat Rascal Hospitality which employs all the staff, creates the menus and determines the style of business.
He said the garden project to date has cost around £35,000, all organised and paid for by Fat Rascal Hospitality.
He added: "The only reason I stress that is that although we don't own the actual building, the business is privately owned and run. There is a perception that we are a chain pub or a managed house, but we are independent."
Tree surgeons Lumber Tree, MA Burrows Joinery and Building Services, and Fenton Engineering all had a hand in creating the new space.
Jason said the pub is all set to re-open on July 4, with new partition screens, outside crowd barriers and signage and banners.
"I think we should be all set!" he added.