Aravot are generally considered to be Salix Alba, White Willow.
They reproduce via what look like small berries at the leave nodes called catkins.
If the willow is healthy and thriving, they look visually like small berries and are filled with very tiny seeds, like fruit would be.
I can report from personal experience that aphids love these things as they ripen, but they are not like actual fruit that one would consider like food. They only serve the willow for reproduction.
On that note, there is discussion in Midrash of a change that will occur at some point during the days of Moshiach. That certain plants that previously bore no fruit, will start to manifest fruit.
These miraculous fruit are called gluska’ote in addition to the other type of gluska’ote mentioned in the Torah which were incredibly large, flavorful and aromatic. Accordingly to the reports from Midrash, these fruits will have miraculous curative properties.
Here is a link detailing the white willow: white willow