Which royal house used the white rose as its badge?

The House of York used the white rose as its badge.

The white rose was adopted as a heraldic badge by Edmund of Langley, the first Duke of York, in the fourteenth century. Edmund was a son of Edward III and the founder of the Yorkist branch of the Plantagenet family.

The badge became strongly associated with the dynasty during the Wars of the Roses, the series of civil conflicts between the rival houses of York and Lancaster. Lancaster was conventionally represented by a red rose, while York was represented by a white one. These floral symbols helped give the later historical name “Wars of the Roses” to a conflict that contemporaries did not generally describe in those terms.

The white rose should not be confused with the Tudor rose. After Henry Tudor defeated Richard III at Bosworth in 1485 and married Elizabeth of York, the Tudor monarchy promoted a combined red-and-white rose as a symbol of dynastic union. The white rose also remains a major regional emblem of Yorkshire, where it appears on flags, civic arms, and public symbolism.