Moonglow

It only grows on jungle grass, and it only blooms at night. Harvest a grown plant while it is dark and glowing and you get seeds along with the herb. Harvest it dull and you get the herb alone, with nothing to replant. A regrowth staff or axe raises both halves of that yield, which is the difference between farming it once and farming it forever.

Night is also when planted stock matures fastest, so a row of planter boxes checked each evening outperforms a large plot you visit whenever you happen to walk past. Clay pots work the same way if you would rather keep it indoors.

Rather than gathering a research batch of every herb, research a single Garland, duplicate copies of it and run them through Shimmer. It breaks apart into the herbs that went into it, which covers the whole set in a fraction of the time.