Also known as Carolina jessamine or Carolina wild woodbine, yellow jessamine (Gelsemium sempervirens) is a robust plant with slender vines that scramble over a trellis or fence. Masses of striking, sweet-smelling yellow flowers appear in late winter and early spring. The state plant of South Carolina, yellow jessamine grows in U.S. Department of Agriculture plant hardiness zones 6 through 10. Propagate yellow jessamine by taking semi-hardwood cuttings in mid- to late summer.
Cut 1 1/2- to 2-inch-long semi-ripe stems with sharp, clean pruners or a knife, making the stems about long. Cut the stems just above a node, which is a small protrusion where a new leaf is about to grow from the stem. Choose semi-ripe cuttings from a healthy, actively growing yellow jessamine plant. At the semi-ripe stage, stems have not hardened, but are still soft and flexible. Morning is the best time to take cuttings because the stems are well hydrated.
Remove the lower leaves from each stem, but leave one or two leaves at the top.
Fill a 4- to 5-inch planting container for each cutting with well draining potting mixture, such as equal parts peat moss and fine bark or perlite. Spray the potting mix until it is slightly moist.
Peel a sliver of bark from the bottom of each stem cutting with the tip of a sharp knife, making a wounded area about 1/8 inch long or less. Remove only the outer bark and don't cut into the tender center of the stem. The wounded spot helps the cutting take up moisture and hormones.
Dip the bottom of each stem in powdered, gel or liquid rooting hormone. Use your finger or a pencil to make holes in the potting mix around the inside edge of the planting container.
Plant a cutting in each hole with the leaves just above the surface of the potting mix. Make sure the leaves don't touch the potting mix or the other leaves. Pat the potting mix around the cutting and water lightly to settle the cuttings.
Place the pot in indirect light at normally warm room temperatures. Water as needed to keep the potting mixture evenly moist but dripping wet. Alternatively, you can maintain humidity by covering the pot with a plastic bag sealed with a rubber band. If you cover the pot with plastic, open the bag for 10 minutes twice every week to prevent buildup of moisture that may rot the cuttings.
Move each cutting into a 3-inch pot filled with regular commercial potting soil when new growth appears -- usually in about one month. Continue to keep the cuttings in indirect light. Water as needed to keep the potting mixture lightly moist.
Feed the new plants once every month throughout the remainder of summer, using 1 teaspoon of a general-purpose garden fertilizer per 1 quart of potting mix. Decrease the amount of fertilizer to 1/2 teaspoon per quart of potting mix during the winter. Check the fertilizer label for brand-specific instructions.
Plant the young yellow jessamines outdoors the following spring or early summer. You can also transplant the vines into a larger, 1-gallon containers and let them continue to mature for another year. As a general rule, newly rooted plants don't bloom for the first three years.