The word "Uchikake means "long overgarment". The word "Iro" means "color". The typical Iro-Uchikake has a red background with vibrant and colorful embroidery of birds, flowers, pine trees, and other symbols that are significant to Japanese culture.
This kimono I have depicted is a more artsy Uchikake. First off, it is "Yaegasane" style. That means that the kimono has multiple folds that are different colors at the collar, hem, and the sleeves. This gives the kimono a layered look. The word "yaegasane" means " eight layers" and refers back to the old court days when noble men and women wore layers and layers of beautiful kimonos.
Secondly, this kimono is pink. there are plenty of Iro-Uchikake that are not red, but the red has become the poster image that PPL think of when you say "Uchikake"
P.S. I'm in no way bad-mouthing the red Iro-Uchikake.