Observe the plant as a whole to notice if it has the common identification qualities of garden sage: small shrub growing no taller than 2 feet height and spreading 1-2 feet wide.
Come closer to the herb and observe its leaves and stems for the following characteristics found in sage: purple or green woody, square stems covered in a fine down. Leaves have a leathery texture also covered with soft hair and are stalked and opposite. When observed closely, they show a network of veins on both sides of leaf and their color depends on the variety of herb (mentioned above).
Rub leaf between thumb and index finger to gather scent on skin. Sniff for the characteristic lemony smell of sage.