Stevia is a plant that produces leaves with a very sweet taste. The leaves are used in cooking and to sweeten teas and other beverages. The plant grows to 36 inches tall and is considered a tender perennial in USDA horticultural zones 9 and 10. In USDA horticultural zone 8 it dies to the ground in the winter, but grows from the roots when weather warms in the spring. Stevia can be propagated by dividing the roots during the winter with a sharp shovel. Also, it can be propagated by taking a cutting in spring. Propagating by cutting works best if done during a time when the cutting is exposed to increasing day length.
Fill a container with water to hold your stevia cutting.
Take a cutting from the stevia plant in spring when the plant is actively growing. Take a cutting from new growth that is not too green or too woody. If the cutting is too green and fresh it will wilt, and if it is too woody it may have trouble rooting. Slice the stem with a sharp knife under the third leaf node, counting down from the top of the plant. A leaf node is the area where the leaves are growing from the stem. The cutting will be about 3 inches long. Immediately place the cutting in the container of water to prevent it from drying out.
Prepare the planting medium by filling a container with drain holes in the bottom with a sterile potting mix or new potting soil. Both sterile potting mix and new potting soil will have lower levels of pathogens that can attack the tender roots of the cutting as they grow. Soil taken directly from the garden is not sterile. Soak the planting medium with water and let drain.
Prepare the cutting by making another cut with a sharp knife under the second leaf node. Then, pull off the leaves that are attached to the second leaf node, counting down from the top, with a quick downward motion to expose the inner plant tissue to the rooting hormone. Immediately dip the cut end of the stevia cutting into the rooting hormone. Make sure the node where you removed the leaves and the cut end are covered with powdered rooting hormone. Stick the cut end of the stem into the planting medium deep enough so the area covered with rooting hormone is covered with the damp planting medium. Push the planting medium around the cutting with your fingers so it is held firmly in place.
Set the planted cutting in a bright area that is exposed to daylight and remains between 65 and 80 degrees F until the cutting roots in four to six weeks. Do not set in direct sunlight. Keep the soil around the cutting moist but not wet during the rooting process.