せいようはこやなぎであれば
西洋箱柳であれば
seiyōhakoyanagideareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of せいようはこやなぎ

1. If it were a Western box willow:; If [it] is a Western box willow:

Ba Conditional
Usually Written in Kana