classic waka stream

where white dew falls
and even showers pass through—
upon that mountain,
not a single lower leaf remains
but all are turned to autumn hues.

Meaning
On the mountain where not only white dew but even autumn showers pass through, even the lower leaves have all changed their colors without exception.
Commentary
Book Five Autumn Poems (Part Two)

Composed near Mount Moru.

In those times, it was believed that dew and rain caused leaves to change color. Playing on the name “Moru” (to leak or pass through), the poem suggests that dew and rain seep down from the upper leaves to the lower ones, coloring them all. Thus, even the leaves below have turned without exception.

“Itaku” means “greatly” or “intensely.”
Author
Ki no Tsurayuki
Source
Kokin Wakashu
Other