Q&A: Out-of-Control Dracaena

I have a dracaena plant in my living room that has grown very tall. Its bare trunk looks ugly. I prefer to see its leafy top, but its up too high. If I cut the trunk, will a new top grow?—EV, Fla.

Answer: Instead of cutting off the top, you need to essentially cut off the bottom. But first you need to get the plant to form a new root system closer to its leafy top. This is achieved through air-layering. This also works on many other trunked houseplants, such as croton, schefflera and rubber tree.

You’ll need a knife, rooting hormone powder, a matchstick, sphagnum moss, electrician’s tape and plastic wrap.

Here are the steps:

Making a cut in the stem will stimulate the growth of new roots. Select a point on the stem approximately 6 to 12 inches below the growing tip, where the stem tissue is sturdy but not hard and woody. A location just below a leaf node is ideal.

With your knife, make an angled cut upwards into the stem tissue, slicing about one-third of the way through it. You may have an easier time making the cut if you turn the plant on its side. Dust the cut with rooting hormone powder. Insert the matchstick into the wound to keep it open and prevent it from healing.

To create the moist conditions necessary for root growth, mold two handfuls of moist but not dripping sphagnum moss into a football-shaped mass around the wounded stem. Be sure to push some of the sphagnum into the cut.

Wrap the moss in plastic wrap, taking care to bunch the ends tightly. To prevent evaporation, secure the top and bottom of the plastic with the electrician's tape.

If the stem seems wobbly, insert a stake alongside the stem, and gently tie the two together. Place the plant in a spot that is bright but not sunny, and water it as usual. The plastic wrap should keep the moss sufficiently damp, but it is a good idea to check it occasionally. If the moss appears dry, open the top of the plastic, add a little water, and reseal the plastic with fresh tape.

If all goes well, new roots should form within the moss in about 8 to 10 weeks, depending on time of year and temperature. When the plastic is almost full of roots, separate the new plant from its parent by cutting through the stem just below the new roots, with a knife or pruning shears.

Choose a pot that is slightly larger than the new rootball and fill it a third full with a mix of three parts moist potting soil and one part sand. Carefully remove the plastic and moss from the roots and immediately put the plant into its new pot. Gently firm more of the potting mix around the roots. Water the plant and place it in a lightly shaded, warm place, where it will be protected from drafts and direct sun.

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