Treerose was a pretty female red squirrel resident of Redwall Abbey and the wife of Oak Tom. In her youth, Treerose was very vain, being known as "the perfect Miss Efficiency". Although she could be snippy and conceited, Treerose was a great cook and often helped in the Abbey kitchen.
She was known for being able to charm most male creatures, including young Saxtus and Dandin. She was therefore surprised when she failed to impress Rufe Brush, whom she particularly admired. Treerose was upset when Storm Gullwhacker became the center of attention at the Abbey, and even accused the fierce mouse of attacking her, hoping, without success, that Rufe would rescue her.
Finally, after Rufe coldly rebuffed her advances (leading to her crying), Treerose stopped being selfish and started to be a more caring and responsible creature. When Colonel Clary, Brigadier Thyme, and Hon Rosie organized a final mission to rescue a group of oar slaves taken hostage by searats, Treerose joined Rufe Brush and Oak Tom to assist the hares. During that time, the squirrel got along well with Hon Rosie. After she witnessed the heroic trio sacrifice their lives in order to save the slaves and protect their escape, she openly wept at the deaths of Clary and Thyme and helped bury them. She also scouted with Tom and assisted Mother Mellus and Flagg in bringing Rosie back to the Abbey to be treated for her injuries.
At some point, Treerose fell in love with Oak Tom, as she wed him and the two left the Abbey to live reclusively in an unknown region of Mossflower Woods.