[Lalaith]

Here is a quote from one of Tolkien's letters which I think is interesting:
What happened to them is not resolved in this book. ... I think that in fact the Entwives had disappeared for good, being destroyed with their gardens in the War of the Last Alliance (Second Age 3429-3441) when Sauron pursued a scorched earth policy and burned their land against the advance of the Allies down the Anduin. They survived only in the 'agriculture' transmitted to Men (and Hobbits). Some, of course, may have fled east, or even have become enslaved: tyrants even in such tales must have an economic and agricultural background to their soldiers and metal-workers. If any survived so, they would indeed be far estranged from the Ents, and any rapprochement would be difficult - unless experience of industrialised and militarised agriculture had made them a little more anarchic. I hope so. I don't know.
[The Letters of J.R.R. Tolkien, 179 (#144)]