Gardening with Laurie: Try air-layering to reproduce plants
July 14, 2010 at 2:14 a.m.
By Laurie Garretson
Midsummer is a great time to air-layer any of your houseplants that have gotten leggy. This procedure is believed to have been developed long ago by Chinese gardeners. Air-layering allows you to root larger pieces of plants than you can root from cuttings. Air-layering will induce the stem of a mother plant to produce roots, while still being attached to the plant. This process not only reduces the size of a large overgrown plant, but you also get new plants at the same time.
Houseplants, such as crotons, ficus, rubber plants, dieffenbachia and dracaena, are commonly air-layered. Woody plants, like magnolia, holly, hibiscus, camelia, azalea, and many types of fruit and nuts, can also be air-layered. Air-layering is generally not used on plants that easily root by other methods.
For best results on woody-type plants, choose limbs that are about pencil size or a bit larger. You'll need a very sharp knife to make two parallel cuts into the stem about 1- to 2-inches apart. Cut all the way around the stem, through the bark and outer cambium layer of the stem. The outer cambium layer is located just beneath the bark. Once you've made this wound, you'll be able to remove the ring of cut bark. Now, the inner layer of trunk tissue is exposed.
The process to air-layer houseplants is done the same way as for woody plants, but you will take the method one step further. In the exposed area of stem, use the sharp knife to make an upward, slanting cut about halfway through the stem. You will then put some damp sphagnum moss in the slit. The sphagnum moss will stay there to hold the wedge open.
The next step is to wrap the wounds in sphagnum moss that has been soaked in liquid seaweed for several hours. Squeeze out the moss of any excess moisture before putting a handful of it all around the stem to cover the wound. Next, take a piece of plastic wrap and wrap the damp ball of sphagnum moss. Use string or twist ties to secure both the upper and lower ends to seal the moss in as well as possible. The damp moss inside the plastic will provide the right conditions for root development.
The actual rooting time will vary. Usually count on at least a couple of months for a stem to produce a good root system. This all will depend on the type of plant and the seasonal conditions. When the new root system is visible on all sides of the moss ball, it's time to remove your new plant from the mother plant.
With a sharp knife or sharp clippers make your cut just below the ball of moss. Carefully remove the plastic covering from the moss ball. Now, your new plant is ready to be planted. Use a good potting mixture if planting in a container (as for houseplants) or well-amended soil if planting directly into the ground. Houseplants will adapt better if you will keep the new plant in a shady location for a couple of weeks. This should be enough time for the new root system to become well established.
Newly-rooted woody plants will also transition easier to the new environment if potted and then kept moist and shaded for a couple of weeks. After the new plant is established, gradually harden it off by exposing it to brighter areas a few days at a time until it's receiving the amount of sun the mother plant gets.
Until next time, let's try to garden with nature, not against it, and maybe all our weeds will become wildflowers.
Laurie Garretson is a Victoria gardener and nursery owner. Send your gardening questions to email@example.com or in care of the Advocate, P.O. Box 1518, Victoria, TX 77902.