Posted on by tonytomeo · 8 Comments

Air Layer Overgrown Houseplants.

Air layering big houseplants, like these lanky rubber trees, keeps them proportionate to limited space while also propagating new plants.

Most of the favorite houseplants are grown for dense evergreen foliage. Stems of Chinese evergreen, anthuriums, bromeliads and most ferns should never be seen. Yet, there are many houseplants that grow like small trees or coarse vines. Various ficus, dracaenas and philodendrons can get too big for their situations if not pruned. Palms can not be pruned down, so can only be moved or given to friends with higher ceilings.

Pruning and discarding overgrown but slowly growing stems seems like such a waste. Technically, stems from almost any overgrown houseplant can be rooted as cuttings. In reality though, most rot before they develop roots.

‘Air layering’ is probably the most efficient technique of propagation of houseplants from overgrown stems. It involves rooting the stems while still attached to the original plant. In the end, an unwanted stem gets pruned away as a freshly rooted new plant.

Air layering needs a bare and manageable section of stem that is at least a few inches long. This section does not necessarily need to be where the stem will eventually get pruned away from. It can be a bit higher (or farther out from the origin) if a shorter copy (new rooted plant) is desired. The extra length of stem in between can be pruned out when the copy gets separated.

The stem should be notched up to a third of the way through. This notch will develop roots better if rubbed with rooting hormone. A big wad of wrung out damp sphagnum moss a bit larger than a softball then gets wrapped around the notch, and then wrapped in plastic film. A cut up freezer bag should work nicely. The bag should be held in place with plant tie tape or something as simple as electrical tape, wrapped firmly around the stem above and below the sphagnum moss. Smaller stems can get smaller wads of sphagnum moss.

Unfortunately, there is no way to disguise the unappealing wrapped moss during the few months that may be needed for roots to develop. Eventually, roots become visible through the plastic, or the moss becomes firm with roots. The newly rooted stem can then be cut below the roots, unwrapped and potted as a new copy of the old houseplant. The stub below can be pruned away, or left to develop new shoots.

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Posted on by tonytomeo · 4 Comments

Make Copies Of Favorite Plants

Honeysuckle can layer naturally, and will most certainly layer if a portion of stem is simply buried or weighed down under a rock.

Where they grow wild in riparian environments, box elders, willows and cottonwoods are not as clumsy as they seem to be. As the rivers and creeks that they live so close to erode the soil around them, they often become destabilized and fall. Yet, this is actually part of their plan. If their original roots remain somewhat intact, the limbs and trunks develop new roots where they touch the ground. Eventually, these rooted limbs and trunks develop into new and separate trees.

In home gardens, a similar technique known as ‘layering’ can be employed to propagate one or a few copies of many other plants. Many sprawling vines and ground covers, such as ivy, honeysuckle, blue rug juniper and trailing rosemary, are likely to develop roots where their stems touch the ground anyway. Rooted stems need only to be found, dug and separated as new plants. Shrubbier plants need a bit more help.

Azalea, rhododendron, camellia, holly and just about any plant that has low stems that can be bent downward into the soil can be propagated by layering. Redwood, elm and magnolia do not always have limbs that reach the ground, but any that do would be pleased to cooperate as well. In fact, there are only a few woody plants that do not develop roots by layering, such as some pines and most eucalypti.

A layered stem only needs to be partly buried to develop roots. The tip should protrude from the soil a few inches. A short stem may barely protrude above the soil. A layered stem of a plant that develops adventitious roots very efficiently can be as long as a few feet. A very flexible stem can easily be held down by the weight of the soil that it gets buried with. A more rigid stem may need to be held down with a rock.

Before getting buried, the stem should be cut about a third of the way through to promote development of roots. The cut should be made on the underside so that it stays open when bend downward and buried. A bit or rooting hormone powder applied to the open wound accelerates the process. It works almost like taking a cutting, but without completely separating the cutting from the parent plant right away.

Once buried, a layered stem should be watered regularly until it gets dug while dormant (or mostly dormant) the following winter. By that time, the rooted stem can be dug and pruned from the parent plant, and then planted where desired. Because it takes a few months for enough roots to develop, layering should be done in spring.