Friendship and Botany

So I met a guy named Willis during my stay up here during the summer. Not met as in serious meeting more like "Hey, can you unlock this door for me?" So I did and we've kept talking and have done some casual hanging out since then. So a few days ago he asked me on a date, I told him I couldn't go. When he asked why I told him it was because he asked in a text message. So a couple days after that happened he came to my house and brought me a potted plant which I recieved when I got home. Oh dear! I didn't know what to do so we named the flower Karina and I texted him and asked, why did you bring me a plant? "because they were throwing them out at the ricks building and I thought you would like it." Since I didn't know what to say but I figured a gift required a thank you, and I also wanted to make sure he wasn't getting any wrong ideas of more than friendship so I said "oh! well thank you for this kind gesture of friendship and botany." I think it is very silly. Now I just need to find a way to make it clear to him that my interest is not as deep as his. oh dear..