I got hit with a baseball right in the back of the skull, I saw two of everything for a week and I still had to carry a block of ice home every afternoon.
The answer is:
It implies that the cherry trees are a new addition to Washington, D.C.
The term novel means new or extraordinary in an interesting way. Besides, cherry trees do not grow naturally in Washington D.C. Actually, they were sent by people from Japan as a token of friendship to the USA in 1912.
