Introduction

What is Plant Layering?

Plant layering is a vegetative propagation technique used to propagate plants by encouraging a stem or branch to develop roots while still attached to the parent plant.

This method involves bending a flexible stem down to the soil surface, wounding it slightly, and covering it with a rooting medium like potting soil or sphagnum moss to induce rooting.

Common layering techniques include simple layering, tip layering, air layering, and compound/serpentine layering, each suited to different plant species and growth habits. In tip layering, the shoot tip is buried in the soil while the rest of the stem remains above ground, promoting root development.

Unlike root cuttings, which involve severing part of the plant, layering allows the new plant to form its own root system while still connected to the parent, offering a more reliable method for propagating plants with specialized structures or woody plants like flowering quince and rubber plant.

Why Choose Layering for Plant Propagation?

Layering is an excellent choice for plant propagation because it allows for the development of new plants with their own root systems while still attached to the parent plant. This method is particularly effective for woody plants, such as flowering quince and rubber plant, as well as for plants with flexible stems like the heart leaf philodendron and spider plant.

Layering techniques, including simple layering, tip layering, and air layering, facilitate root formation without the need for root cuttings, making it a reliable method for producing new plants with specialized plant structures.

By using a rooting medium like potting soil or sphagnum moss and ensuring proper conditions, such as those provided in early spring, layering promotes successful root development and minimizes the risk of plant loss.

Types of Layering Techniques

Simple Layering

Simple layering is a straightforward plant propagation technique where a flexible stem of the parent plant is bent and buried in soil while still attached to the parent. This method works well for a variety of plants, including woody and herbaceous species like purple and black raspberries, spider plants, and heart leaf philodendrons.

By encouraging roots to form along the buried stem, new plants develop their own root systems, making them independent once severed from the parent. Gardeners often use peat moss or potting soil to mound the stem and may use rooting hormone to induce rooting.

Simple layering is typically done in early spring or during the dormant season, yielding new plants in a few weeks to months.

Mound Layering

Mound layering is a plant propagation technique where a stem of the parent plant is partially buried in the ground, forming a mound of soil around it. This method is effective for plants with horizontal stems, such as purple and black raspberries or closely branched shrubs.

By encouraging roots to form along the buried stem and ensuring it remains attached to the parent, new plants develop their own root systems over time. Gardeners often use potting soil or peat moss to mound the stem and may apply rooting hormone to stimulate root formation.

Mound layering is typically performed in early spring or during the dormant season, resulting in newly developed roots and eventually independent new plants.

Serpentine Layering

Serpentine layering is a plant propagation technique suitable for long arching stems or vine-like plants. In this method, portions of the stem are buried intermittently along its length in shallow trenches or mounds of soil.

This encourages the buried nodes to produce roots, thereby creating new plants that remain attached to the parent until they establish their own root systems. Serpentine layering is effective for woody plants like flowering quince or herbaceous perennials, as it utilizes the plant's natural growth pattern to induce rooting at multiple points.

Gardeners often use rooting hormone and cover the buried sections with soil or sphagnum moss to facilitate root formation during the growing season.

Air Layering

Serpentine layering is a propagation technique where a flexible, long arching stem is buried intermittently along its length just below the soil surface. This method encourages the nodes to form roots at each buried point, resulting in multiple new plants connected to the parent through a rooted stem.

It's effective for a variety of plant species, both indoor and outdoor, particularly those with thick stems or long arching growth habits. Unlike traditional stem cuttings, serpentine layering utilizes the plant's natural ability to produce roots along its stem, making it a reliable propagation method even with plants that have dormant buds or bulbs.

Selecting Plants for Layering

Best Plants for Simple Layering

When selecting plants for simple layering, consider shrubs and groundcovers that readily develop new roots from their stems when buried in mound soil.

Ideal candidates include creeping juniper and cotoneaster for groundcovers, and for shrubs, species like hydrangeas and viburnums which have flexible stems conducive to layering. Use a sharp knife to wound the stem at the shoot tip, apply rooting hormone, and bury the wounded portion in soil or a rooting medium to induce root formation.

This technique, often referred to as simple layering bend, works well for both indoor and outdoor plants, leveraging natural layering processes to establish new plants with their own root systems.

Best Plants for Mound Layering

When considering mound layering, both vines and woody perennials offer great options for propagating new plants from rooted stems. Vines such as wisteria and ivy can easily form roots at the soil surface when their stems are buried in mound soil or covered with a rooting medium like sphagnum moss. 

Similarly, woody perennials like hydrangea and climbing roses respond well to mound layering, allowing their stem tips to develop new roots and establish themselves as independent plants.

This propagation technique is effective for both indoor and outdoor plants, utilizing natural processes to encourage root formation and growth from the parent stems.

Best Plants for Serpentine Layering

When considering serpentine layering, certain plants excel in propagating new plants from rooted stems. Plants like creeping fig and English ivy are ideal candidates for this technique due to their flexible stems that easily bend and form roots along the soil surface or in a rooting medium.

This method works well with indoor plants that benefit from the supportive structure provided by serpentine layering, allowing new shoots to develop along the parent stems.

Unlike cuttings, which require severing the plant, serpentine layering allows for layering stems to remain attached while establishing roots. Outdoor plants such as groundcover roses also thrive with serpentine layering, utilizing natural layering techniques to establish new roots and propagate effectively, just as other plants can benefit from this approach.

Best Plants for Air Layering

When choosing plants for air layering, select those with woody stems and the ability to form roots readily in a rooting medium or wrapped in moist sphagnum moss and covered with aluminum foil.

Ideal candidates include fruit trees like citrus and guava, which develop new roots along the stem above the soil surface. This method is effective for both indoor and outdoor plants, facilitating the propagation of new plants without the need for severing from the parent stems.

Air layering, or creating an air layer, is particularly advantageous for plants with thick stems or long arching stems, allowing them to produce rooted plants that can be easily transplanted once roots develop.

Protecting the Roots and Your Plants

If you're looking for a low-risk, low-cost way to propagate your garden plants, try the technique called layering. This is one of the effective propagation techniques that allow you to establish a good strong root system on the new plant before separating it from the mother plant.

Unlike other methods such as cuttings and grafting, layering ensures that roots form while the new plant remains attached. Additionally, using twist ties can help secure the stem in place during the process.

And unlike dividing, only the new layered plant will be relocated, thus keeping the mother plant's root system intact and undisturbed, making it an excellent option for asexual propagation.

Plants That Propagate by Layering Naturally

Numerous plants (such as cane berries, strawberries, and ivy) naturally propagate by layering, and others (including many flowering shrubs, herbs, and trees) can be induced to form new plants either by ground or air layering.

• Blackberries-tip layer. If allowed to grow and touch the ground, the lateral branches will start to produce roots at the point that comes in contact with the soil.
• Strawberries-runners are formed that eventually form a new plant and root.
• Succulents-some produce offshoots that result in new daughter plants (hens and chicks come to mind).

Methods of Ground Layering

There are several types of ground layering you can try.

• Simple layering
• Tip layering
• Serpentine (compound) layering
• Mounding (stooling) layering
• French layering

All layering, except with plants that naturally form adventitious roots such as runners, should be wounded to encourage root formation along the stem or branch. Wounding simply involves removing or breaking a bit of bark or the outer layer of the stem, either by peeling off a small piece of the stem, making a small sloping cut into the stem, or twisting the stem until it cracks. The wound should be made on the bottom side of the stem or branch, as this is where the roots will emerge. Root formation can be further encouraged by coating the wound with a rooting gel, which contains naturally occurring hormones that trigger root growth. For ground layering, you can additionally irrigate with Rooting Solution regularly until well rooted.

Simple Layering Method

• Usually done in the autumn or early spring.
• Select a stem that is one or two years old, wound it, and bend it down to the ground.
• Pin it in place and lightly cover it in soil, ground staples work well.
• Alternately, you can dig a shallow trench into which it will be pinned.
• The daughter plants are typically ready to sever from the mother after a few months to a year.
• In autumn you can separate them out to root up in individual pots, or transplant them directly into the ground in the spring when the soil has begun to warm.

Tip Layering Method

• Some plants, such as cane berries, prefer to root at the tip instead of mid-stem.
• Dig a hole 3-4" deep and insert the tip of the shoot.
• Cover with soil
• Examples of plants that is readily propagated are purple and black raspberries and blackberries.

Serpentine (Compound) Layering Method

• Done in the same way as simple layering, except that multiple points are rooted along the same stem.
• This method is good for plants that produce long shoots each year, such as clematis, and creates more daughter plants than simple layering.
• To achieve this, wound and bury the stem (in the same way as with simple layering) between each node or bud.
• Good for plants that produce vine-like growth like grapes, wisteria, heart-leaf philodendron or pothos.

Stooling Layering Method

• Hard prune a shrub in late winter and mound the shoots with soil in spring when they’ve grown to 6–8 inches in height.
• Roots will then grow on each shoot where it is buried.
• The following autumn, the mounded dirt is removed and each shoot is pruned off and planted individually.
• This method works well with daphne, spirea, apple rootstocks, magnolia and cotoneaster.

French Layering Method

• A type of stooling that produces several plants per stem.
• After hard pruning in the early spring, the shoots are allowed to grow for a year.
• The next spring, trim off the growing tip, bend the shoots horizontally, peg them to the soil and bury them.
• Each shoot will grow roots and produce numerous side-shoots (new vertical stems).
• The side-shoots are repeatedly mounded through the summer to a final depth of 6 inches of soil.
• In the autumn, the side-shoots are dug up, separated, and planted individually.

Mounding Layering Method

• Very similar to stooling, except that the plant does not need to be hard pruned, and the rooted stems are ready within a few months.
• In the spring, bury the plant except for an inch or so of the top.
• By late summer, the stems will have formed roots.
• Dig them out, cut them off from the parent plant, and transplant them.
• This method works well for old, woody perennial herbs like thyme, rosemary and lavender, and for closely branched shrubs like flowering quince.

Air Layering Method

• Used on tree branches and other elevated stems that cannot be bent to ground level, and for plants that are difficult to root by other means.
• Use on plants such as camellia, citrus, and rhododendron.
• This can be done in the spring on the previous year’s growth, or in the late summer on the current year’s growth.
• It will be most successful on branches that are at least pencil-width.
• Remove the leaves in the section to be rooted, wound the bark, and cover the site with a 4 inch-thick layer of moist sphagnum moss.
• Then enclose the moss in sturdy plastic wrap that is sealed on both ends.
• Once roots have formed and are visible through the plastic, remove the plastic (but not the mossy layer)
• Prune off the branch just below the moss, and transplant it.
• This can take as little as two months or up to a full year, depending on the plant.

Conclusion

In conclusion, plant layering offers gardeners a versatile method to propagate a wide variety of plants effectively. Whether using simple, mound, compound/serpentine, or air layering techniques, each approach allows new plants to develop their own root systems while still connected to the parent plant. For example, tip layering works well with long flexible stems, making it an ideal choice for many trailing or climbing species.

This method ensures higher success rates compared to other propagation methods like cuttings or grafting, particularly for woody plants and those with specialized structures. By using materials such as plastic wrap to protect rooting areas, gardeners can further enhance the conditions for successful propagation.

By leveraging natural growth processes and appropriate conditions, gardeners can expand their plant collections with confidence, preserving the health of both parent and newly propagated plants throughout the process.

FAQs About How to Propagate Plants by Layering

• What is plant layering?
  Plant layering is a propagation technique where a stem or branch of a parent plant is encouraged to develop roots while still attached. This allows the new plant to form its own roots before being separated from the original plant.

• Which plants are best suited for layering?
  Plants with long flexible stems, like the swiss cheese plant and dumb cane, are ideal for simple layering, where the stem is bent and buried in soil. Woody perennials such as hydrangeas and climbing roses thrive with mound layering, while vines like wisteria benefit from compound/serpentine layering, where stems are buried intermittently to stimulate root formation.

• How does air layering differ from other propagation methods?
  Air layering involves removing a portion of the bark from the main stem and wrapping it with rooting media and a plastic sheet to facilitate rooting. Unlike stem cuttings, layering allows new plants to develop roots while still attached, ensuring a higher success rate for many plants.

• How does tip layering work?
  In tip layering, the stem tip is buried in the soil while the rest remains above ground. This method is effective for ensuring a good root system develops along the buried portion of the stem.

• What materials are needed for successful layering?
  Basic materials include a sharp knife for wounding stems, rooting hormone to stimulate root growth, and a suitable rooting medium like peat moss or potting soil. Using twist ties can help secure the stem in place, while clear plastic can protect the rooting area from too much sun.

• When is the best time to perform layering?
  Layering is typically done in early spring or during the plant's dormant season to coincide with active root growth. This timing helps ensure that newly developed roots establish themselves before the onset of harsh weather conditions.

• How long does the rooting process take?
  The rooting process can vary depending on the plant species and the layering technique used. Generally, it takes several weeks to a few months for roots to form, at which point you can cut the rooted cuttings from the parent plant and place them in a separate container.

• Can layering be used for all types of plants?
  While most plants can benefit from layering, some species are better suited for this technique. It's always good to research specific plants to determine if layering is the most effective propagation technique for them.

• What should I do if the layered stems don’t root?
  If the layered stems don’t root, ensure they have sufficient moisture and are not exposed to too much sun. You may also consider applying fresh rooting hormone or checking the rooting media for proper drainage.