Cut off any leaves on the stem from the bottom 2 inches with pruning shears. Place the stem cutting in a glass and add water to about 2 inches deep. Place the glass in an area with filtered light to allow the cutting to grow roots. Add water as necessary to maintain the 2-inch level in the glass.Cuttings are ready to plant when they have several roots that are about 3/4 inch long.nsert a trowel into the soil around the drip line of the salvia plant. Dig straight down into the soil. Continue digging around the entire plant in a circle to severe any roots from the root ball.