The garden's location outside the old city wall also offers a glimpse of a rather more ordinary, less touristy Marrakech than that around the exciting, noisy and colourful Djemaa el-Fina plaza at the heart of the city's medina.
Out here school students and shopkeepers jostle for space on rugged footpaths, children dodge taxis and donkey-drawn carts on the horn-blasting roads, and pedestrians amble hand-in-hand across intersections and roundabouts between a chaotic implosion of scooters, cars, trucks, buses and carts. All of which make Jardin Majorelle an even more restful respite amid the heat, haste and dust.
Although Berge and Saint Laurent - whose ashes were scattered in the garden in 2008 after his death in Paris - are most commonly associated with this very special place, it takes its name from the original owner.
The artist Jacques Majorelle bought the property in 1924, when Morocco was still a French protectorate and began landscaping the sandy soil. He brought together a dizzy array of local and imported plants, offsetting them with the astonishing blue paint, which today takes his name, on the buildings. Equally striking however is the burnt orange or vivid yellow of large vases which are deliberately placed in corners against the "bleu majorelle" walls where the contrast can be dramatic. You can't be in a hurry in this garden where bougainvillea and jasmine drape above your head because there is so much small detail to enjoy.
Coupled with clear light on a cloudless day, Jardin Majorelle is a photographer's dream location as hard edges of pure flat colour shimmer in bold contrast.
Doubtless the light and warmth of Morocco were part of what drew Saint Laurent and Berge here, but the designer also found the familiar. He was born in Oran, Algeria, where he lived until he moved to Paris at 18. So in Morocco he used the vibrant local colours, textiles and designs of North Africa which he adapted for many of his dresses in couture collections from the mid-60s onward.
Some of his clothing conspicuously referred to the djellaba, those ankle-length, hooded robes familiar in so many Muslim countries and visible everywhere on the streets of Marrakech.
Saint Laurent also designed turban-like headwear and was drawn to the bright flat colours or multicoloured broad stripes of Moroccan material.
"When Yves Saint Laurent and I arrived in Marrakech for the first time in 1966," said Berge in 2008, "we didn't know this town would play such an important part in our lives, that we would buy three properties there. Nor did we know that Morocco would become our adoptive country, our second home."
The couple - then partners, later separating but remaining in business together - bought Jardin Majorelle in 1980. It had slid into neglect and disrepair after the death of its original owner and they set about restoring it - with the help of, among others, the American architect and designer Bill Willis.
A long-time Marrakech resident and notorious drug user who counted a few Rolling Stones and writer William S. Burroughs among his friends alongside various Rothschilds and Getty millionaires, Willis - who died in 2009 - was a close friend of Saint Laurent and Berge and designed villa interiors for the power couple in Marrakech.
"We used to drive up to the mountains near Marrakech," he said. "We would see Berber peasant women carrying their bundles of firewood who wore the most wonderful colour combinations - [Saint Laurent] inspired himself a lot from that."
The extent of Saint Laurent's passion for the colours of this country was evident in an exhibition at Jardin Majorelle in November 2010 which featured 44 of his Morocco-inspired haute-couture designs, all notable for their vivid tones. Often he found new inspiration in the colours of the city where rich blues, pinks, reds, gold and orange are so prominent.
"This city led me to colour," Saint Laurent once said of Marrakech. And later he observed, "There are gardens in Marrakech, for which I have a real passion. And the colours that I miss in Paris."
For the designer, Jardin Majorelle was also a retreat from his increasingly debilitating lifestyle in Europe, which was fuelled by his cocaine and alcohol addiction, although initially it seems he hardly moderated his intake while in Marrakech.
Here, in the gardens he loved, he felt at ease. Photographs of Saint Laurent at home frequently show him bare-footed or in sandals, wearing a djellabah and relaxing with ever-present cigarette packets close to hand.
Often he would come here immediately after showing a collection in Europe to relax and perhaps - Berge has described him as a manic depressive - to collapse. Jardin Majorelle was a place where a man could live softly and unassailed. The walled garden offered solitude, safety and the possibility that for days, if not weeks, the public man could be private.
These casual days and nights were rare in a life of fastidiously dressing up, and of fashionably dressing others.
French socialite Christine Alaoui who conducted soirees for the visiting glitterati at her Marrakech home Bled Roknine knew Saint Laurent well and observed how, over time, the country changed him.
"Yves spent significant time in Morocco after his life had slowed down and he stopped partying," she said. I knew him in a very different way from many others. He was calm, introspective and personal. He revelled in the simplicity of life here."
Last December an important new addition was opened at Jardin Majorelle: the Berber Museum, housed in the spacious ground floor of Majorelle's former painting studio. Here, under muted lighting, are mannequins dressed in the handsome or rustic finery of the Berber people, many dozens of examples of their silver jewellery displayed along with historic photos, film footage from the middle of last century, domestic artefacts, musical instruments and weaponry.
In their clothing you can see hints of what might have impressed Saint Laurent. They possess an exoticism, certainly, but once past that impression, in the loose cut, their often asexual nature and the easy flow of the garments you can see suggestions of their strong influence on Saint Laurent's eye.
Then you just add colour.
Since Majorelle - who died in France in 1962 - opened his garden to the public in 1947, this special place has been a refuge for one of the most important designers of the 20th century whose foundation now manages it. Today is a magnet for plant lovers, the curious and even those just in search of a quiet place in a noisy city.
Some even go for the poster art of Yves Saint Laurent in the Galerie Love beside the boutique, I suppose.
• Graham Reid flew to London with assistance from Cathay Pacific but paid for his own trip to Morocco.
- VIVA