Although closely related, white sage (salvia apiana) and common garden sage (salvia officinalis) are different in both appearance and use.
The mature leaves of a white sage plant are smooth and white, while the leaves of garden sage are gray or gray/green. Also white sage is slightly larger, growing 4 to 5 feet tall compared to garden sage's 2 feet height max.
White sage flowers are mostly white with hints of lavender, while garden sage flowers are usually purple or bluish-purple (although they can sometimes also be lavender or white).
White sage is native to the southwest and prefers dry, almost desert conditions, while garden sage is native to the Mediterranean and Spain and needs regular watering (not drought tolerant).
Both white sage and garden sage are used for ornamental and medicinal purposes, but white sage is also often used as incense, while garden sage is most commonly used as a seasoning in recipes.
There are over 800 known varieties of salvia (sage).