Yūka Izumi is the president of the gardening club and the only member aside from Kenichi. and is currently a second year student at Kōryō High School.
She is a shy girl who harbors a crush on Kenichi, though he is oblivious to it. Her attempts to ask Kenichi on a date are always interrupted. She is relatively a friendly and kind-hearted young girl that is also polite and rather shy, especially when it comes to Kenichi. She heard of the rumors about him, but after getting to know him, she knew they were wrong and accepts him for who he is. Her feelings eventually develop to love, though Kenichi doesn't share the same feelings. Despite this, he cares for her very much as a friend and is always kind to her and worries over her well-being, such as being enraged when Daimonji used her as a hostage and was determined to save her.
In Ryōzanpaku, she is jealous of Miu because Izumi is in love with Kenichi, so she joined in on the plan Niijima created. She's also a little jealous of Miu's figure and how well-endowed it is compared to others and herself, wondering how she has such a figure for someone so young. Despite this, she and Miu are good friends and she cares about her just as much as Miu does to her. Though she seems to be aware of Kenichi's feelings and relationship with Miu, she respects him enough to choose who he wants to be with, but that doesn't stop her from trying to win his affection.
Izumi is a young teenage girl of average height with long black hair she has in two braids in the back with some fringe in the front. She is typically seen in her school uniform at school or her swimsuit at school and is always seen with her glasses on.
Izumi is first seen when Kenichi decided to join the garden club and told him about the rumors she heard about him, which he denies. After getting to know him better, she develops feelings for him and enjoys his company and his love for plants. She is then used as a hostage by Daimonji to lure Kenichi out and when he defeats him, she thanks him for saving her and comforts him when all the plants are destroyed.
When she was swimming with her fellow classmates, she notices Miu with them and shows her envy on how close she is with Kenichi and how well-endowed she is, admitting she wants to know of her relationship with Kenichi and Miu states their good friends.
In Episode 16, she is with Kenichi in the gardening club but was interrupted Miu, Izumi is suprised when she learns Miu and Kenichi live together at Ryōzanpaku.
At the end of Episode 23, Izumi said that she will fight for what she wants and she will train (it is unknown if she will do this) and will try to be the right girl for Kenichi.
During the Yami arc, Izumi is typically seen in the garden club with Kenichi and her attempts to ask him on dates are usually interrupted, leaving her depressed. She becomes happy when Chikage decides to join and, like Kenichi, warms up to her and become good friends. Chikage tells Izumi, after witnessing her failed attempt for going out for a movie, she'll be Kenichi for a while and once she found his weakness, she will tell her so she can win his affection, because she owes her one for the plant seeds and allowing her to borrow the flower bed.
When Miu was saved from the Demon Fist and returned home, Izumi noticed that Miu and Kenichi had become closer. She was surprised by Ukita who notice the same thing, but tell her that there is no need to restrain herself when she like someone which encourage her to keep trying to win Kenichi affection.