Jien spent a half hour resting and meditating to get his mind back in order. He did not spend a particularly large amount of mana to perform the essence extraction, as it wasn't necessary to do so if one had decent control. The strain was in terms of exerting that control against a living being. An inanimate material wouldn't fight against the alchemist but something that was living would always wish to remain living, and thus the struggle between the material and the alchemist would be in terms of focus and control.
Once Jien had rested and recollected himself with mild meditation he opened his eyes, looking at the Serpent Vine specimen he had chosen for this first attempt. The Serpent Vine had grown larger from its initial status as a sapling. It now sat on a small table a few feet away from him as its length had increased enough to make it necessary. The first thing he did was cast a spell covered in the alchemy guide for calming living plants for splicing. This was to make sure that their resistance would be minimized and in the case of the Serpent Vine, to ensure that it wouldn't attack him while he worked.
He waited for a few minutes after casting the spell and watched as the vine curled around the small table as if it were the trunk of a tree. Jien knew that this was the sign that the plant was 'resting' and so stepped closer carefully while holding the jar that contained the Creeping Moss essence. Once he was within about a foot distance from the vine he sighed slightly in relief that the plant did not 'wake up' and attack him.
He sat on the floor and put his hand on top of the lid of the jar, injecting some mana into it while still keeping it bound under his control. He used his mana to surround the white mist, containing it gently but firmly. He removed the lid of the jar and used his mana to draw the essence out into the open once more while continuing to maintain control. Now would start the hard part. He would have to work on joining the essence of the two plants.
For this process he needed to send forth a second thread of mana into the Serpent Vine. He knew already what he was trying to do. He was going to use the aggressive nature as well as the nature of the two plants' natural environments being similar to create the initial connection. This part would require him to carefully draw out the properties of the Serpent Vine essence without actually extracting it, something that he had only just recently had actual success in during his experiments in splicing common plants.
Jien slowly and carefully extended the tendril of mana into the vine before him, watching it carefully to ensure that it wouldn't attack him out of the blue. He only relaxed slightly when he felt the slight connection between his mana and the plant.
He focused deeply on using his mana as a type of sensory organ to find the correct aspects of the vines essence, something that took him over fifteen minutes of direct focus. After finding those portions he slowly and cautiously started to draw them to the surface. Though it wasn't too visible in the well lit room Jien could sense as the small wisps of light were drawn to the surface of vine. After he made sure that he wasn't damaging the plant in the process by looking over its length as attentively as he could he decided to move forward with the next step.
He focused on the properties of the Creeping Moss essence that were the closest to those that he had drawn from the Serpent Vine. This process was vastly easier as the plant itself was 'dead' and he could shift his mana through its essence without any resistance in the least.
After he had identified the correct portions and drawn them out of the essence of the moss much like loose threads of ghostly mist he focused on the next step in the process. He used his mana to float the bundle of white mist close enough to the vine to continue. He then focused on the threads representing the two plants' aggressive nature, using his mana to draw the threads together and wrap them around one another as if braiding hair.
He did not rush in doing this. Though it was a large strain on him to keep this level of control over his mana in an external environment he remained as utterly focused as he could be. After the first threads of essence were intertwined thoroughly he moved on to the next and then the next after that until he finally bound all the points that he felt were strong enough for the fusion to succeed.
After he was done with connecting the different threads he poured his focus into the cloud of essence from the Creeping Moss. He had successfully made the connection between the two plants but he did not want all of the parts of the creeping moss to be present in his finished product, what he wanted was the moss's ability to expand its size. For that he would have to cut out all of the extra pieces which mostly would encompass its growth patterns and adaptations to different stimuli.
He spent about an hour slowly dissecting the cloud of white mist, unraveling it like a smokey ball of yarn until it was just small bundle no larger than his pinky with several threads reaching out to the vine.
Jien could truly sigh in relief at this point. Though he had only gotten one part of a long project taken care of he felt good about his accomplishment. He used his mana attached to the vine to carefully reel in the strings of essence that he had drawn out of it. As they drew inward they pulled along the tangled essence from the moss until it was swallowed. There was no spectacular event to prove his success but Jien knew that the splicing had indeed worked, it was just a matter of if the plant would evolve in the way he hoped.
Despite his joy over the first success he knew that his project was just starting. He took a break before turning his eyes to the Magic Mandrake. His hopes on making a more easily controllable final product were at least partially reliant on it.