The overall tone of this song is of a relationship/love that has grown cold and distant.
'lightning struck' is an allegory to a situation, circumstance or revelation that has caused a rift in the relationship. People can grow together or apart. Regardless, they have both quit on their relationship and as the person repeats, 'i know we'll grow, but we"ll never bloom again' indicates surety that although they can move on (grow) they could never thrive (bloom) together.
The overall tone of this song is of a relationship/love that has grown cold and distant. 'lightning struck' is an allegory to a situation, circumstance or revelation that has caused a rift in the relationship. People can grow together or apart. Regardless, they have both quit on their relationship and as the person repeats, 'i know we'll grow, but we"ll never bloom again' indicates surety that although they can move on (grow) they could never thrive (bloom) together.