I wouldn't, TreeHead isn't the best defender, and if used, Confusion is a must and as an attacker you really need Extrasensory/Solar Beam (which isn't worth the dust either if you already have a Z/SB), unless you want a pure grass attack one with the other new attack.
Sad story, one my only 100 IV mons and I'd power him up if I saw value even at low level, while useful, just not worth it!