I don’t remember the name and I want to find it again. A and B are childhood friends. I remeber they are in university. A gets a girlfriend and B loves A. B is in the planting club and he gives up and wish A happy. One day, on the way home, B nearly get into the accident with a truck. A begins to regret what he has done. Finally A and B have a happy ending. Please help me!!!(≧∀≦)
If its yaoi maybe its this one. Its similar to your description but they were not in a gardening club.
http://www.mangago.zone/read-manga/kataomoi_to_parade/
This manga is a well-written story. All details are connected with each other to create a new arc. Cannot wait to have more. I also hope after this spies arc we will get to know more about Sano and Ebisu-sensei (๑•ㅂ•)و✧