Oh, I'm so glad to hear you say that, because I've had an idea for a while about their collaboration, sparked by thoughts of just how did the trees grow tall about Melian and Thingol while the rest of Middle-earth lay under the Sleep of Yavanna. I just haven't had the motivation to write it yet, so your comment has given it a boost! Thank you!

They do seem an obvious collaborative pair, don't they? I've been researching Ulmo, and I haven't yet come across anything that puts them directly together. The closest I've yet seen it come is In The Beginning Of Days where the paragraph about Ulmo's power nourishing life even under the darkness of Melkor, is immediately followed by the paragraph describing Yavanna going at times to heal his hurts.

Thank you, I like your point about Ulmo. I think that although it is said that he has not ceased to take thought of those in Middle-earth, in these primordial days before the coming of the Children he was probably mostly skulking about the deeps still.

Yay! Glad you think so too. More Ulmo and Yananna coming up!