Gardeners who live in regions where it stays warm year-round often grow salvia successfully as a perennial plant. When you have a healthy salvia plant growing in your landscape, propagate new salvia plants with cuttings from the mother plant. Within approximately one month, you can have vibrant new salvia plants suitable for outdoor planting with little effort or expense.
Cut a stem from the salvia plant. Make the stem between 2 and 8 inches long and cut the stem off just after a leaf node (the junction where a leaf intersects with the stem).
Fill one glass of water for each stem with approximately 2 inches of water.
Place one stem into each glass so the bottom of the stem (the cut edge) is beneath the water level.
Place the glasses in a location that receives indirect sunlight. Check the water levels each day and replenish the water if it falls below 2 inches.
Fill the planting containers with potting soil. Spray the surface of the potting soil with the spray bottle to moisten the potting soil.
Make an indentation in the centre of the potting soil for the cutting and the roots.
Remove the cuttings from the glasses when the cuttings have roots that are between 1/4 inch and 3/4 inch long. Place the cuttings directly into the prepared containers and firm the soil gently around the roots.
Place the large plastic bags over the containers, making sure the bags do not touch the cutting foliage. Secure the bags to the rims of the containers with rubber bands.
Place the containers back into the same indoor location with indirect sunlight. Spray the soil once or twice each day with the spray bottle to keep the soil moist.
Remove the plastic bags from the containers after one week and allow the salvia plants to continue to grow in the containers for one to two more weeks. Keep the soil evenly moist with the spray bottle.
Harden the plants off to the outdoors for approximately one week before you transplant them. Move the containers outdoors to a location with shelter from the sun and wind. Leave them in this location for approximately three hours and bring them back inside. Gradually over the next week, lengthen the time the salvia spend outdoors and move them to a location where they receive more sunlight and wind.
Move the new salvia plants to a permanent outdoor location after you harden them off. Choose a location that receives morning sun and afternoon shade. Plant the new salvia plants at the same depth as they are growing in the individual containers. Water the newly transplanted salvia plants generously immediately after you transplant them.