Snip a cutting from healthy new growth anywhere on a coleus plant. Ensure the stem of the cutting is straight. Do not pinch the growing point.
Push the cut end of the cutting into a 2-inch pot filled with equal parts vermiculite and peat moss. Put the pot in a protected, partially shady location, and keep it watered until roots form in two to three weeks.
Fill a 6-inch pot with quality, indoor potting soil. Insert a bamboo stake near the center of the pot, offset to one side by 1 to 2 inches. The bamboo stake should be the same height as you want the final height of the trunk of the coleus.
Remove the rooted coleus from the 2-inch pot, and plant it in the center of the 6-inch pot, near the bamboo stake.
Tie the coleus loosely to the bamboo stake with strips of raffia.
Place the coleus in partial shade in a protected location. Continue loosely tying the stem of the coleus to the bamboo stake as it grows. Do not remove any leaves along the stem at this time. Fertilize the plant weekly with a water-soluble houseplant fertilizer, mixed at half the strength stated on the label.
Pinch the growing tip of the coleus when it grows just beyond the top of the bamboo stake. This will cause it to branch out, beginning the process of creating a canopy on your coleus tree.
Pull off the leaves along the "trunk" of the coleus after it begins growing new branches.
Pinch the growing tips of the branches in the canopy, removing the beginning of leaf set number four, when each branch has three sets of leaves. New growth will continue from the junctures where the leaves grow from the stems, creating a thick, lush canopy.
Transplant the coleus into an 8- to 10-inch pot when the root system outgrows the 6-inch pot.