I've decided to take on another task for the Royal family on behalf of Count Jooliin in the Lesser Faydark. He's tasked me with taking a blessed seed into the Shadowed Grove, planting it and then collecting the plant that sprouts. This seed must be very valuable if Queen Amree was keeping this in her private vault. For her to give up this seed in such a fashion only tells me that the void influence is greatly troubling her.
Take the seed of growth to the Shadowed Grove and plant it there. There are two locations (right or left of the entrance). Need to stand still a moment on the rocky surface at the entrance before the stubs that show where to plant appear. Note: In graphics settings from High Performance and better, you should see a swirling green circle that shoots mystical runes into the air in the two spots!