Air layering is an easy technique to bring those too-tall houseplants back into a manageable size. This method basically causes the plant to produce roots high up on the stem, then the top part can be severed and replanted as a shorter, compact plant.
Here’s how to do it:
1. Choose the right candidate:
This works on many common houseplants such as dracenas, corn plants, crotons, hedera, rubber trees and schefflera. It should have a tall, lanky stem with the crown of leaves right at the top.
2. Gently wound the stem at the place where you would like the new roots to form. Make a small cut with a clean sharp knife. It works best between 6-12 inches down from the growing tip of the plant.
Make a small nick in the stem, prop it open with a toothpick
3. This area now needs some damp material packed around it to stimulate root growth into: try several handfuls of damp moss. Pack it tightly around the entire stem of the plant, and secure firmly with a covering of plastic held in place on top and bottom by string, tape or twist-ties.
Pack it with damp moss or coir, seal both ends firmly to keep moisture in.
4. Then continue to care for the plant as usual, maybe not giving it too much direct sun as that may dry out the moss. Check to see that it remains damp, but not so soggy as to rot the stem.
5. Be patient – air layering is not a quick process! It can take several months for new roots to develop strongly and become visible through the plastic wrap.
6. When there is strong root growth easily visible, you may cut the plant off just below the plastic-encased root ball, and then pot it up in fresh compost and sand mixed together. Firm it in and stake if necessary until it has become established .
Cut off top when well rooted, and then pot up
7. With the remaining stem, you might want to try taking stem cuttings, and really increasing your stock of houseplants (these can be donated to friends, local schools or hospitals, or to a charity plant sale). Cut the stem into pieces several inches long, making sure to note which end is up (it won’t work if you stick them in upside down). Put them into sharply draining mix of sand and soil, and keep moist. You can put several into a shallow pan and cover the entire pan with plastic to create a mini greenhouse. With luck, most of the stem pieces will root, and can then potted up separately to form new plants.
Once you’ve mastered the technique, you can air-layer many shrubs outside as well as your houseplants – this works well with expensive plants such as rhododendrons, azaleas, magnolias, crab apples, holly bushes and those fragrant witch hazels. David demonstrated the technique on Canadian Gardener on July 25/98, and these two stills illustrate the process on a magnolia tree:
Packing moss around the wound
Sealed in plastic wrap to keep moist
Don’t start until later though – late spring to midsummer works best for outside shrubs. You will have to be even more patient though, as rooting can take one or maybe two years in some cases, but then, what’s the hurry? You’ll have the satisfaction of being able to propagate many plants yourself.