On those sultry days when heat saturates the city, the lush, sprawling gardens of La Mamounia seem even more unlikely, but there’s no doubting this oasis really is embedded in the Red City. Outside the 12th-century ramparts that define this palace hotel garden lie glimpses of the Medina and the Atlas Mountains. Inside, embedded between soaring palms and hundreds of ancient olive trees, lemon, peach, and orange trees spill their scents before providing fresh produce for the hotel’s restaurants.

Behind this Paris palace hotel, Le Bristol's lawns were recently spruced up by Lady Arabella Lennox-Boyd, a UK-based landscape architect who for over 45 years has created more than 600 gardens. Her Jardin Français incorporates only flora native to the Paris region. In spring, guests dining at Epicure overlook a flush of narcissi and tulips; white bougainvillea and dewy pink roses flourish in summer; coppery beech leaves emerge in fall; and a canopy of evergreens takes center stage each winter.

A former medieval monastery divinely embedded in the Fiesole hills that overlook the city, Florence’s Villa San Michele still feels like a sanctuary. That atmosphere is one that was cultivated by the first Franciscan monks 600 years ago, with the same view of Il Duomo. Today, the wooded park surrounding the hotel’s terraced lawns has matured beautifully; artworks new and old are spread across the gardens; and the fragrant bushels of wisteria that bloom twice a year are “only” four centuries old.

The Bulgari’s extensive but unshowy gardens have something of a split personality: at times they’re a verdant refuge, peaceful as can be; visit during Milan Fashion Week or Salone del Mobile and the people-watching is pure theater. In any season, the grounds’ drinking and dining areas effortlessly facilitate standout socializing. They include suntrap Vimini, bordered by a stretch of trimmed laurel trees, and Le Isole de Ghiaia, where folds of white wisteria are draped around plane trees.

Wedged between the pretty mini-city of Valletta and the urban sprawl that surrounds it, The Phoenicia’s recently completed gardens make for a far more pleasant amenity than the minigolf course that stood in their place and are a welcome sight in a sun-soaked country that is generally devoid of lush greenery. Planted with colorful flora that can withstand Malta’s arid climate—think oleander, callistemon and lantana—lawns here are shaded by jacaranda, orange, palm and olive trees.

Spread across four Ottoman-era buildings and with the remnants of an ancient Roman villa in its garden, Arthaus Beirut is Lebanon’s most distinctive boutique hotel. Shaded by a spread of mature trees and with a swimming pool at its core, the property’s golden courtyard is cool and calm by day, but becomes notably more lively on hot summer evenings when patrons gravitate here for al fresco cocktails—or to admire whatever artworks the property’s discerning owners have newly installed.

Located just a corgi toss from Buckingham Palace, London’s last remaining family-run luxury hotel has long drawn old-school English aristocracy—its pedigree was cemented when Catherine Middleton stayed over the night before her wedding to Prince William. In hot weather, guests sip Pimms and perhaps play croquet on its immaculately manicured garden; staff proudly share that it’s bigger than Centre Court at Wimbledon.

An American who has called Bangkok home for decades, hotel designer Bill Bensley’s lifelong love of greenery and Thailand are entwined at The Siam. Flanked by a three-storey atrium, a tranquil pool at the hotel’s center is bordered by a forest of soaring banana palms and cascading ferns. Three century-old teakwood houses have been transposed to the hotel’s back lawn, a serene setting from which to drink or dine and observe the barges and boats that sail down the Chao Phraya River.

A green lung in the Pink City, Rajmahal Palace’s 10-acre gardens are a refuge from the excitement and intensity to be found on the streets of one of India’s most popular destinations. Shaded by scarlet-petaled gulmohar trees and perfumed by fresh jasmine, in cooler months the grounds are occasionally booked by well-to-do locals for jubilant, colorful wedding parties—a sight to behold—or can be enjoyed by guests during leisurely outdoor breakfasts or high tea.

In the tranquil garden found at the center of this recently opened hotel, discreetly embedded stone lanterns and rocks add robust texture and tension to a setting that is otherwise a tribute to the soft serenity of nature. Bordered by a shallow pool of water and carpeted with moss, lawns hold profusions of Japanese blue oaks, red pine and bamboo year-round, but are arguably at their most beautiful come spring, when for a few glorious weeks they are covered by a burst of cherry blossom.