This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
艻 combines the plant radical 艹 with 力, but the exact historical development is uncertain. It may have originally been a phono-semantic compound, but the modern form is rare and its origin is not well documented.
The top 艹 suggests a plant, and the bottom 力 suggests strength. Picture a strong, resilient plant, but remember that the actual meaning is unclear.
For ロク, imagine a strong plant that looks like a rock: rock -> ロク, and the plant's strength makes it as tough as a rock.