僕は啄木の詩の多くを暗記した。

English Translation

I learned many of Takuboku’s poems by heart.

暗記した is not bad, but 暗唱した(あんしょうした)is better. 暗記する sometimes implies that the person memorized it without understanding the true meaning in depth. 暗唱する, on the other hand, means “to memorize the lyrics or poems and be able to sing/express them without thinking”.