Willie Nelson -- I Got a Ton of Green for Sale

Willie Nelson is unloading a few million dollars worth of green, he's got 20 foot high trees to help sweeten the pot -- and this is NOT about marijuana.

TMZ has learned Willie's golf course in Spicewood, Texas called Cut & Putt just went up for sale ... and he's asking for $3 mil.

The 75 acre property has a 9-hole course, a country club and a recording studio. The listing also boasts trees (non-cannabis variety) ranging from 20-40 feet tall.