Highgarden

"You must see Highgarden. You'd love it there, I know you would. We have a great masquerade the night of the harvest moon... you should see the costumes, people work on them for months."

- Margaery Tyrell to Sansa Stark

Highgarden is the seat of House Tyrell and the regional capital of the Reach. Located on the banks of the river Mander, Highgarden sits astride the Roseroad, a major thoroughfare linking Oldtown and King's Landing. Highgarden also forms the southern terminus of the the Searoad, which leads to Lannisport. As King's Landing, Oldtown, and Lannisport are the first, second, and third largest cities in the realm, heavy trade and traffic across a large swath of southern Westeros ultimately passes through Highgarden.

Background
Highgarden was founded by Garth Greenhand, one of the legendary kings of the First Men. His descendants, House Gardener, ruled from Highgarden as Kings of the Reach until the invasion of Aegon the Conqueror. King Mern IX Gardener and all his issue were slaughtered by Aegon's dragons on the Field of Fire, and his steward Harlen Tyrell yielded the castle to Aegon. In gratitude, Aegon bestowed Highgarden on the Tyrells and named them Lords of the Reach. This sparked off a long-standing complaint from House Florent of Brightwater Keep, who claimed a superior blood-link to the Gardeners, though this has been constantly dismissed by later kings.

Season 2
During the tournament held by King Renly Baratheon, when Ser Loras Tyrell duels with Brienne of Tarth, Margaery Tyrell cheers on her brother by standing up from her seat and shouting "Highgarden!".

After Renly is assassinated, most of his bannermen from the Stormlands submit to his older brother Stannis Baratheon. However, Margaery and Loras withdraw House Tyrell's sizable army back to Highgarden, along with the other Houses from the Reach they command. A few Tyrell bannermen, however, bend the knee to Stannis.

Season 4
When Jaime Lannister returns to King's Landing, Cersei enumerates the many grievances she has suffered in his absence, and voices her extreme displeasure at Joffrey marrying Margaery, whom Cersei deems "a wicked little bitch from Higharden".

Notable residents of the castle

 * Lady Olenna Tyrell, known as the Queen of Thorns, the dowager-lady of the house. Formerly Olenna of House Redwyne.
 * Lord Mace Tyrell, the ruler of House Tyrell, eldest son of Lady Olenna.
 * Margaery Tyrell, Mace's only daughter, reputed to be a beautiful maiden, close to her brother Loras.

In the books
In the A Song of Ice and Fire novels, Highgarden is among the most beautiful castles in the Seven Kingdoms. Situated on a broad, symmetrically shaped hill, the castle includes three concentric tiers of white stone walls, which increase in height and thickness as one travels upwards. Between the outermost and middle walls is Highgarden's famous "briar maze", a labyrinth of beautifully maintained hedges that serves two important purposes; entertainment for the castle's inhabitants and deterrence against enemies (any invaders who manage to penetrate the outer wall would have no easy task finding their way through the elaborate growth of thorns and greenery).

The inner rings of Highgarden are a beautiful complex of towers, courtyards, colonnades and statuary, and greenery is just as prominent inside the walls as in the fields outside; ivy, grapevines and climbing roses can be seen snaking around the buildings, and gardens and arbors are filled with flowers. Water is also a common feature inside the walls; pools, fountains and even man-made waterfalls can be seen throughout the complex.

Highgarden is also notable for its places of worship. The castle sept is lined with rows of stained-glass windows depicting the Seven as well as Garth Greenhand, the legendary first king of the Reach. Highgarden's godswood, instead of the typical single heart tree, contains three tall weirwood trees known as the Three Singers. Said to have been planted by Garth himself, the branches of the trees have become so enmeshed over the centuries that they resemble a single tree with three trunks.

A fine selection of horseflesh can be found in Highgarden's stables, and pleasure barges offer river cruises on the Mander. Outside the walls, meadows and fields of flowers can be seen in every direction, along with fruit orchards rich in peaches, melons and fireplums.