Short answers, pulled from the story.
Henry VII created the Tudor rose to present himself as a peacemaker king after his marriage to Elizabeth of York in January 1486. Historian Thomas Penn notes that Henry adopted the Tudor rose conjoining the Red Rose of Lancaster and the White Rose of York on his marriage.
The Tudor rose represents the union of the House of York and the House of Lancaster following the Wars of the Roses. The design features five white inner petals for York and five red outer petals for Lancaster to signify peace between the two warring factions.
An Order in Council dated the 5th of November 1800 established the crowned and slipped Tudor rose as the royal floral emblem of England. This specific version appears on the dress uniforms of Yeomen Warders at the Tower of London and Yeomen of the Guard.
The design features in the 20-pence coin minted between 1982 and 2008 and appears in the royal coat of arms of the United Kingdom and Canada. The Supreme Court of the United Kingdom uses it alongside other floral badges representing Great Britain and Northern Ireland.
The borough and county of Queens in New York City uses a Tudor rose on its flag and seal while Annapolis Maryland features a Tudor rose and thistle surmounted with a crown on its flag and seal. The city of York South Carolina is nicknamed The White Rose City while nearby Lancaster South Carolina is called The Red Rose City.