I didn't make it in time for cherry blossoms but, this is for you.
「桜の季節に間に合わなかったけど（贈り物は）私の気持ちです。」は英語で「I didn't make it in time for cherry blossoms but, this is for you.」という表現が一番自然だと思います。
桜の季節ーCherry blossom season
間に合わないーToo late for・Didn't meet
贈り物ーGift・Present
私の気持ちーMy feelings・My thanks
I meant to give you this during cherry blossom season, but I didn't. It's just a little something from me.
この場合、次のような言い方ができますよ。
ーI meant to give you this during cherry blossom season, but I didn't. It's just a little something from me.
「これを桜の時期に渡すつもりだったのに渡せなかったの。少しだけど私の気持ちです」
during cherry blossom season で「桜の時期」
ご参考まで！
アメリカ合衆国 
カナダ 
