Yamato Nadeshiko Shichihenge♥

It's a gorgeous, spacious mansion, and four handsome, fifteen-year-old friends are allowed to live in it for free! There's only one condition—that within three years the guys must transform the owner's wallflower niece into a lady befitting the palace in which they all live! How hard can it be? Enter Sunako Nakahara, the agoraphobic, horror-movie-loving, pockmark-faced, frizzy-haired, fashion-illiterate recluse who tends to break into explosive nosebleeds whenever she sees anyone attractive. This project is going to take more than our four heroes ever expected: it needs a miracle! (Source: Del Rey)

Yamato Nadeshiko Shichihenge♥ had twenty-four volumes published in English as The Wallflower: Yamatonadeshiko Shichihenge by Del Rey from October 12, 2004 to October 26, 2010. Volumes 22, 23 and 24 were collected into a single book. Kodansha Comics USA picked up the license and published the remaining volumes from June 21, 2011 to April 26, 2016, and republished the previous ones on August 21, 2012.