Although I live just ten minutes down the road from Glyndebourne, I have only been to see two operas there: a technicolour version of Englebert Humperdinck’s Hänsel und Gretel in which the witch was the cashier in a Roald Dahl-esque sweetie supermarket; and a sumptuous production of Mozart’s Die Entführung aus dem Serail in baroque colours of burgundy and gold.

On both those occasions, I only saw the garden fleetingly as it was either winter or raining. So I couldn’t pass up the opportunity to visit the inaugural Glyndebourne Open Gardens on Sunday, for a modest entrance fee of £10 which goes towards the garden fund. I discover borders as full of theatrical colour as the stage productions.

Under head gardener Kevin Martin and his four man team, the gardens at Glyndebourne are a work of artistic merit in their own right. As soon as you approach the modern auditorium surrounded by a jungle of tree ferns and giant cannas, you are transported to an exotic world a million miles away from the tranquil South Downs.

Coming out of the main entrance area I encounter the Organ Room, which has the graceful yet imposing air of an Oxford college. This opens out onto the terrace in front of the main eighteenth century house, laid by Glyndebourne’s founder John Christie in the 1920s. The planting around this well-trodden path (which is the main route from the coach park to the auditorium) is brilliant and clashing: scarlet dahlias, soft pink cosmos, purple sedums, towering Persicaria orientalis with hot pink flower tassels. From the lawn below you can see frothy blush-coloured roses and clouds of pink and white Erigeron karvinskianus.

The Wild Garden Border forms a bridge between the formality of the house and terrace and the informality of the bucolic pastures beyond, where sheep graze peacefully around a modern sculpture. Orange is the predominant colour here, with flames of Mexican Sunflower (Tithonia rotundifolia ‘Torch’) and yet more vibrant dahlias.

Across the lawn there are beds of blue clematis and salvias and a white border with tall trumpets of Nicotiana – throughout the garden there is a playful approach to height with tall plants popping up like the high notes in an aria.

The garden is designed to be at its best in the summer season when it becomes homes to legions of picnicking opera goers in evening dress, so it is little surprise that the rose garden is a little overblown and past its best.  But there is still plenty to look at: the perfect Alice in Wonderland croquet lawn, the elegant Urn Garden with its contrasts of yellows, pinks and blues, the classical rectangular pool overlooked by a Henry Moore reclining figure and the magical Bourne Garden, Martin’s own favourite part of the garden in late summer, with a heady mix of grasses, more cannas and tree ferns, late flowering salvias, dahlias, asters and Helianthus as well as Verbena bonariensis and Acanthus mollis.

Along the way I stop off at the plant stall run by a local nursery and treat myself to a Aster x frikartii ‘Monch’ and a Sedum ‘Red Cauli’. Finally, I visit the greenhouses which are a little bare at this time of year and the kitchen garden which supplies the table at the big house, where, delightfully, sweetcorn and pale lemon roses grow side by side.

Opera at Glyndebourne is a fixture in the summer season. Let’s hope the Glyndebourne Open Gardens follows suit.