Rosedrop was a chestnut mare bred in England by John Doyle and owned during her racing career by Sir William Bass, 2nd Baronet who bought her as a yearling for 700 guineas.

Her dam Rosaline showed so little promise that her owner Jack Barnato Joel donated her to charity auction in aid of the Fresh Air Fund at which she was sold for 25 guineas by William Allison.

Rosedrop however was not officially named until 1910, and ran as a juvenile under the descriptive title of Sir W. Bass's chestnut filly by St Frusquin - Rosaline.

[8] The filly was still unnamed when he ran in the 1000 Guineas over the Rowley Mile at Newmarket Racecourse on 29 April and finished third of the thirteen runners behind Winkipop and Maid of Corinth (who was also owned by Bass).

Ridden by Charlie Trigg she dominated the race from the start and won "in a common canter" by four lengths from Evolution, with Pernelle a neck away in third.

[10] At Royal Ascot eleven days later Rosedrop was matched against male opposition in the Gold Vase over two miles and finished unplaced behind the colt Charles O'Malley.

[12] At the Newbury summer meeting she led for most of the way in the Kingclere Stakes but was caught in the last stride and narrowly beaten by the colt Lonawand, to whom she was conceding weight.