Yavanna's Chosen

[Raynor]

I see it entirely differently. If we are to judge Radagast on the basis of how well he fulfilled his secondary task of looking out for Yavanna's interests, I would think the Ents would have been the most credible, as they themselves had the fundamental purpose of protecting trees and forests, in line with Yavanna's desire.

Again, ents are very limited in their own focus:

Originally Posted by FotR, Chapter 4

The ents loved the great trees; and the wild woods, and the slopes of the high hills... But the entwives gave their minds to the lesser trees, and to the meads in the sunshine beyond the feet of the forests; and they saw the sloe in the thicket, and the wild apple and the cherry blossoming in spring, and the green herbs in the waterlands in summer, and the seeding grasses in the autumn fields.

We were only a legend to [Men], a secret in the heart of the forest.

The ents' major interest seem to be the really big trees of the forest, while all the rest seem to be outside their concern. That doesn't make them very reliable source tbh. Also, the very fact that they take care of at least the trees in their area, would require very little intervention on Aiwendil's behalf; that, coupled with the fact that ents are rather reclusive and sticking to their own parcel ["we are a legend to [Men], a secret in the heart of the forest"], gives a pretty good reason for their very limited knowledge about his abilities and actions.

We have a single opinion expressed here, by one representative of a race concerned with a limited land, and even there, probably focused on just a few species - everything else, even there (sloe, small trees, green herbs, grasses, etc) seem to escape their notice anyway. If they aren't experts and/or watchers over all these "fields", I don't see why we should be concerned too much with their opinion, if the work of Yavanna has a greater scope anyway.

[Inziladun]

Originally Posted by Raynor

We have a single opinion expressed here, by one representative of a race concerned with a limited land, and even there, probably focused on just a few species - everything else, even there (sloe, small trees, green herbs, grasses, etc) seem to escape their notice anyway. If they aren't experts and/or watchers over all these "fields", I don't see why we should be concerned too much with their opinion, if the work of Yavanna has a greater scope anyway.

I'll concede Treebeard's line, while to me highly suggestive, is in itself not proof of Radagast's failure.
If successful though, even at the secondary task of protecting flora and fauna from Sauron and his armies, why do we not see him taking ship with Gandalf after Sauron's defeat? The Istari, at the end of the day, were the enemies of Sauron, and their primary concern was his fall. Saruman obviously did not fulfill his part in that mission. The 'Blue Wizards' too, we are told, were unsuccessful. It is said that only Gandalf 'remained faithful', and he is the only one of the Istari returning home to the West after Sauron's destruction. Either Radagast couldn't take the ship because he had failed in the Eyes of Authority in the West, or he wouldn't, because he had forgotten both his tasks: the 'official' one, and the 'secret'. If he had accomplished things to Yavanna's satisfaction, surely she could have arranged for him to return home, as the 'secret' mission would have been well known to Manwë.

[Ibrîniðilpathânezel]

Here's something Tolkien had to say on the matter, from letter 156, beginning with a commentary on the incarnate nature of the Wizards:

Why they should take such a form is bound up with the 'mythology' of the 'angelic' Powers of the world of this fable. At this point in the fabulous history the purpose was precisely to limit and hinder their exhibition of 'power' on the physical plane, and so that they should do what they were primarily sent for: train, advise, instruct, arouse the hearts and minds of those threatened by Sauron to a resistance with their own strengths; and not just do the job for them. They thus appeared as 'old' sage figures. But in this 'mythology' all the 'angelic' powers concerned with this world were capable of many degrees of error and failing between the absolute Satanic rebellion and evil of Morgoth and his satellite Sauron, and the faineance of some of the other higher powers or 'gods.' The 'wizards' were not exempt, indeed being incarnate were more likely to stray, or err. Gandalf alone fully passes the tests, on a moral plane anyway (he makes mistakes of judgement).

If, in Tolkien's mind, Gandalf alone succeeded in the mission of the Istari, then Radagast failed -- not in the hideously spectacular way of Saruman, utterly betraying their purpose, but nonetheless falling away from the job he was sent to do. I think, perhaps, the fact that Treebeard mentions Gandalf as being the only wizard who loves trees is really quite telling. The Ents, the Shepherds of the Trees, were brought about as a result of Yavanna's supplication to Manwe (and Eru) for some protection for those things of Arda that she loved (as per the Aule and Yavanna chapter of TS). And yet, when it came to arousing the hearts and minds of the Ents to resistance of Sauron, it fell to two Hobbits rather than to Radagast, who of all the wizards should have been the one to make a specific effort to contact and advise and instruct the Ents. He apparently didn't, and thus failed his mission, as well, perhaps, as Yavanna, who I think would have wanted the Ents to be included among those peoples threatened by Sauron. The trees were the one thing that she selected as most beloved to her, and Radagast would appear to have either ignored or forgotten about them, in favor of his own personal love for birds (which is the meaning of his name as a Maia, Aiwendil).

[Raynor]

If successful though, even at the secondary task of protecting flora and fauna from Sauron and his armies, why do we not see him taking ship with Gandalf after Sauron's defeat?

I don't see why being on that particular ship is any sign of success for his Yavanna-mission or of rejection of re-entry back to the blessed lands. Didn't Gandalf too actually fail, from error of judgement, to getting himself killed and having to be resurrected by Eru? Yet despite his individual failure (transformed into success only due to enjoying spiritual majority with Iluvatar), we still see him on the ship, smiling and waving. Wasn't compassion and clemency shown even to Melkor and Sauron? So why wouldn't it be shown to a fellow maia, especially given a mighty burden, that of an actual body, with all its limitations, weaknesses and temptations that was imposed on him. Surely a lot more understanding would need to be shown in this case by the just valar, for a mission in which they themselves send the maiar to accomplish. Hey, even the Noldor are allowed back into Valinor :x. Also, we have no information that this particular ship is the only one that ever left Middle Earth after Sauron's demise nor that the Istari didn't have any other means of returning besides to Valinor besides jumping on a plank of wood.

The fact of the matter is we do not know how the Yavanna-mission unfolded; it's a black box to us, we don't know what happened there. Even if someone had a palantir at his disposal, to watch every single move that Aiwendil did from the moment he set foot on Middle-Earth to the moment his mortal body eventually perished - even in that case, which of us could claim to know and perceive all the ripple effects of even the most inconspicuous actions? What do we know about the magic of Yavanna, working in this world? About how the fate of the living reign needed sustenance from her emissary? And if we don't know that, how could we claim failure?

I think, perhaps, the fact that Treebeard mentions Gandalf as being the only wizard who loves trees is really quite telling.

I won't repeat the points about how limited the scope of one Ent's knowledge is. And, again, ents should already be taking good care of their parcel, while there is literally the whole of green Middle-Earth to be supported (and not just trees btw). An overlap of 'authorities' and limited resources, of any kind, be they magic or simply of time, doesn't make much sense.

The Ents, the Shepherds of the Trees, were brought about as a result of Yavanna's supplication to Manwe (and Eru) for some protection for those things of Arda that she loved (as per the Aule and Yavanna chapter of TS)

True, but there comes a time when all mythological creatures need to retreat from the world; first the valar, now the elves, and ents wouldn't be an exception to that. Times of great sorrows and mythological enemies require protectors of equal nature. But after the fall of Sauron, they are no longer needed in the world of Men, and ought to retreat.

And yet, when it came to arousing the hearts and minds of the Ents to resistance of Sauron, it fell to two Hobbits rather than to Radagast, who of all the wizards should have been the one to make a specific effort to contact and advise and instruct the Ents. He apparently didn't, and thus failed his mission, as well, perhaps, as Yavanna, who I think would have wanted the Ents to be included among those peoples threatened by Sauron.

Was it known to him, or well, anyone else beforehand, that he had to contact the ents to do this and that? No, so I don't see why it is used against him, if he had no opportunity to start with, that he could refuse. The fact that it was the hobbits who had to meet the ents, and their personal transformation on so many levels, speaks more about their personal mission than about Aiwendil.

The trees were the one thing that she selected as most beloved to her

Her most poignant image relates to the Two Trees, and her image itself is that of a tree, but this relates to the role she had to play at a certain time. However:

Originally Posted by Valaquenta, Silmarillion

She is the lover of all things that grow in the earth, and all their countless forms she holds in her mind, from the trees like towers in forests long ago to the moss upon stones or the small and secret things in the mould