Take a cutting from a healthy crossvine plant in June or July. The cutting needs between six weeks and two months to root before fall transplanting.
Examine your vine for a healthy, insect-free cane. Use the knife to trim a 4- to 8-inch section from its growing tip.
Snip the leaves from the cane's lower 1/2 to 2 inches with the pruning shears. This prevents them from decaying in the rooting medium.
Spread wax paper on your potting table and sprinkle it with rooting hormone. Dip the lower end of the cutting into the rooting hormone. Hold the cane upright and pass it through the hormone so some of the powder clings to its cut surface.
Fill the container with rooting medium. Dig a hole in the center of the medium. Make it wide enough that its edges won't dislodge the rooting hormone from the inserted cutting. Reserve the removed medium.
Insert the cutting into the rooting medium. Secure it by piling the reserved medium into the hole around its base. Water the pot enough to settle the medium around the cutting's base.
Insert the three wooden sticks into the medium at equal intervals around the container's rim. Place the clear plastic bag over the container and secure it with a rubber band. The sticks hold the plastic off the cutting's surface.
Clean fallen leaves from the rooting medium as needed. Syringe the cutting daily with water to maintain the soil's moisture and the plastic bag's humidity. Give the top of the cutting a gentle pull periodically. Resistance means it has begun forming roots.
Remove the cutting from the rooting medium when it has developed two or three 1/2-inch roots. Transfer it to a 4-inch pot containing potting medium and the tree wooden sticks. Perforate the clear plastic bag with several small holes using the fork. Water the pot and place the plastic over it. The holes allow gradual evaporation of the moisture inside the plastic, letting the cuttings adjust to a low-humidity environment. Remove the plastic after a week.
Move the potted cutting outside to a shady location with protection from extreme temperatures. Expose it to increasing sunlight and temperature ranges each day for several weeks, until it has adjusted to outdoor life.