"Growth" was merely a secret art, not uncommon within the Spirit Wood Dao and Spirit Plant Path.
This art had been passed down from the Spirit Farmer Dao before it split into branches. Most of the time, it was used to cultivate seeds and accelerate their germination.
Some seeds were extremely fragile while their embryos developed, or could not withstand changes in the external environment.
At such times, spirit farmers could use the Growth Secret Art to hasten their sprouting while effectively maintaining the stability of the surrounding environment.
Because it amounted to forcing growth, and because one did not wish to compromise the plant's quality, this secret art consumed a great deal of spiritual energy.
When dealing with rare, high-quality plants, it not only consumed spiritual energy, but could also drain a spirit farmer's vital essence and blood.
Useful as it was, it harmed the body too greatly. Even in the Spirit Farmer Dao, sects did not encourage frequent use of this secret art.
Still, most people learned it... once you farmed fields, you needed the awareness of a farmer. When urgency struck, it could come in handy.
Withering and Flourishing... was an upgraded version of the Growth Secret Art, allowing a plant to undergo withering and flourishing in an extremely short time.
Because its growth-accelerating effect was exceptionally strong, this art could be considered a pseudo-divine ability.
But accordingly, its side effects were even greater. If used without restraint several times, at best it would ruin one's foundation; at worst, it would directly shorten one's lifespan.
Those below the Golden Core Stage were not advised to use it. Even Nascent Soul cultivators had to act within their limits. After using it, they had to properly recuperate before using it again.
As for Years, it was an upgraded version