Elko, Nevada
They are between 4 and 5 years old.  His soil was alkaline and hard.
He dug a hole 2 ft wide and 18 inches deep.  It was filled with top soil, peat moss and sulphur (to bring down the pH).  He also used "Ironite" to provide the minerals that are missing in alkaline soil.  For fertilizer the first 2 years 4 tree stakes were used as well as lawn fertilizer.  The owner said lots of  water is the key.