This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
葖 combines the grass radical 艹 with 突, but the historical development and original meaning are uncertain.
The top grass radical 艹 suggests a plant, and the bottom 突 (thrust) might hint at a plant that thrusts upward, but the exact meaning is uncertain.
For トツ, imagine a plant thrusting up so suddenly it makes a 'tots!' sound: tots -> トツ.