House Tyrell of Highgarden is one of the Great Houses of the Seven Kingdoms, overlords over the Reach. A large, wealthy house, its wealth is only surpassed among the Great Houses by House Lannister, and the Tyrells can field the greatest armies. Additionally, if they call the fleets of their bannermen the Redwynes, the lords of the Shield Islands, and the coastal lords, they can command a navy that equals if not surpasses the royal fleet.

Highgarden is an ancient seat of rule and the heart of chivalry in the Seven Kingdoms; the Tyrells style themselves 'Defenders of the Marches' and 'High Marshals of the Reach', and traditionally, they have been Wardens of the South. Their sigil is a golden rose on a green field, and their words are "Growing Strong." Members of the family tend to have curly brown hair and brown or golden eyes. 

Recent Events

On the outset of the novels, Loras Tyrell, the Knight of the Flowers, is the only member of the House outside the Reach. He rides in the Tourney of the Hand, defeating Ser Gregor Clegane but yielding the final tilt to Sandor Clegane after the Hound rescues him from the Mountain. He is upset when the Hand, Eddard Stark, does not send him to bring Gregor to justice for pillaging theRiverlands. As King Robert lays dying, Loras supports Renly Baratheon's desire to take the crown before either Prince Joffrey or Lord Stannis Baratheon can claim it, and flees the city with him when Lord Stark rebuffs Renly's request for his aid.

House Tyrell declares for King Renly. Margaery is to be his queen, his ex-squire and secret lover Ser Loras the Lord Commander of his Rainbow Guard, and Lord Mace his Hand. With the backing of the Tyrells (and almost all of their bannermen), Renly has the strongest army in the War of the Five Kings. After a failed parley with his brother Stannis, Renly's host seems sure to win the coming battle. When he is murdered that night, an enraged Loras kills the two knights who were guarding him. Renly's assassination saw many of the Reachmen defect to Stannis's cause. The Tyrells and their leal bannermen (including Paxter Redwyne, Randyll Tarly and Mathis Rowan) plot their next move at Bitterbridge, where they receive a visit from Petyr Baelish. He extends an offer of alliance with King Joffrey "Baratheon" and House Lannister. The Tyrells join with Tywin Lannister, marching on King's Landing in time to save the city and rout Stannis's forces in the Battle of the Blackwater. Mace's second son Ser Garlan the Gallant fights in Renly's armor, frightening the smallfolk into believing the king had risen from the grave.

After the battle, Mace is rewarded with the small council post of Master of Ships, while lords Redwyne and Rowan are given advisory seats. Garlan is made lord of Brightwater Keep, since the Florents now served Stannis's cause. Loras joins the Kingsguard, and Margaery is betrothed to King Joffrey. Prior to Margaery's arrival in King's Landing, Tyrell men with food carts succor the starving residents, creating wild popularity for her and her house despite the fact that it was the Tyrell embargo that created the shortage in the first place. Mace's mother Lady Olenna arranges to meet with Sansa Stark. Talking to Sansa about Joffrey, Olenna decides she does not care for the match between he and Margaery and conspires with Petyr Baelish to poison Joffrey at his own wedding feast. Tyrion Lannister is falsely accused of the murder, and Mace is one of the judges at his trial. He wants the Imp dead because Margaery was drinking from the same cup, unaware that it was his mother who perpetrated the poisoning, but Tyrion eventually escapes the city.

Since then House Tyrell has indeed "grown strong", coming to dominate their tenuous alliance with the Lannisters despite the paranoid meddling of Queen Cersei. After her father the Hand's death, Cersei resumes her regency and removes Mace and his favored bannermen from the small council. Meanwhile Margaery is wed to the new king, Joffrey's brother Tommen, releasing Mace from his vow not to leave the city until Margaery was wed. Margaery makes a point to win the love of the people and to try and prepare Tommen for kingship; she is baffled by Cersei's refusal of all her suggestions and apparent lack of understanding regarding dire military threats. She resists the attempted seductions of Cersei's agent Osney Kettleblack. Cersei sends Loras to besiege Dragonstone and Mace to besiege Storm's End to remove them from the capitol and place them in danger. Loras is badly wounded while seizing the island, and Mace quickly returns when he hears that Margaery has been imprisoned by the High Sparrow, she and Cersei exchanging mutual accusations of immorality. By the time he arrives, however, he finds Randyll Tarly has already secured her release; Tarly is to hold them until their trial. He again vows to remain in the city, this time until Margaery is acquitted in her upcoming trial. With Cersei imprisoned, Ser Kevan Lannister is named Lord Regent over Tommen, and he takes several steps to smooth over Cersei's actions. Mace Tyrell is finally made Hand, and his bannermen Randyll Tarly and Paxter Redwyne are made masters of laws and ships, respectively. Ser Kevan is now dead by crossbow thanks to Varys, which The Spider hopes will lead to continued fracturing of the Lannister-Tyrell alliance.