Early Quenya
tasarin
noun. willow
tassarin
noun. willow
lailekse
noun. willow
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
A word for a “willow” in Early Qenya Word-lists of the 1920s, appearing beside the more usual “willow” word ᴱQ. tassarin (PE16/139). There is no sign of lailekse outside of this 1920s document.