Is weed considered a performance enhancing drug in pro golf?

Leafsfan29-Embrace the drought!

Yes. Because golf is on the Olympic programme, the professional golf tours (PGA Tour, European Tour, LPGA Tour) all follow the WADA protocols for tests (as of 2017 they now test blood whereas they used to just test urine). Having said that, the tours are notably lax for publicizing details about positive tests. Example being Dustin Johnson a few years ago. There were multiple reports that he had tested positive for cocaine on three occasions, but the PGA Tour never announced a suspension. Instead he took a 'voluntary leave' from the tour. Vijay Singh was suspended for using deer antler spray, sued, and his suit against the Tour was settled last month (the original test was 8+ years old). None of this means that professional golfers don't smoke marijuana (FWIW one of the drugs that was in Tiger Woods' system when he was arrested for DUI was THC, which is the active ingredient in marijuana).