A shadow-infused herb is received from clearing dead herbs from a herb patch while a farmer's Catalyst fragment or a combined Catalyst fragment is equipped. Clearing dead patches in Herblore Habitat does not provide any shadow-infused herb.
Between 188 and 934 Farming experience is received when clearing a dead patch with the Catalyst fragment equipped at level 99 Farming. This results in a range of 2-6 shadow-infused herbs, with an average of 3.8 herbs. These herbs can be cleaned for Herblore experience, thus destroying the herb in the process. A stack of up to 60 herbs can be cleaned in a single click, thus larger stacks require multiple clicks to clean. Between 109 and 191 Herblore experience is gained per herb, at level 99 Herblore.