The first verse is less potent that Spreagadh might have hoped, the flames clinging to the treant's shell mitigating the chill somewhat. There's still a definite crunching audible as the resins in it's stone armor freeze and expand and a hiss of pain from the treant itself, but it's not going to do the living tree in anytime soon. Not by itself.
As the fey launches into her second verse the treant completes it's own machinations, roaring forth a single word in it's own incomprehensible tongue. Controlling the forces of nature without direct contact is tricky, as is controlling even such low sentiences as insects, hence why it took the treant so long, but with a little searching it's found the perfect mind to commandeer for it's purpose.
The incantations effects are not obvious, no roaring winds or scorching flame here, but within the thick layer of fallen leaves beneath Spreagadh's tree, something stirs. Slithering up the trunk opposite to where the fey sits comes a dire centipede, long as a man's arm and all in dull gray-black armor, trying to crawl up behind Spreagadh and sink it's mandibles into her flesh, spreading a paralytic poison.
This alone would be a poor tactic as the fey would no doubt spot the insectile assassin on it's own. So the treant calls forth another spell in quick succession, this one simple and easy, yet with the flash, the flair the situation calls for. Drawing upon the light of the sun it hurls a beam of brilliant, searing light towards Spreagadh. It's easy enough to dodge, barely coming close enough to wing her should she stay still, but it's true purpose is to distract and briefly blind her so the true attempt upon her life might succeed.