Water Rooting in Plants: A Deep Dive into Propagation Techniques

Using Rooting Hormones and Comparing Water v. Soil Propagation.

Plant propagation is an essential aspect of commercial growing, and a fun activity for hobby propagation. For homeowners, it can result in significant savings when plants are literally “home-grown” versus purchased. 

Among the many methods available, rooting plant cuttings in water stands out as a popular and accessible technique. This blog explores water rooting in detail, lays out its advantages and drawbacks, and compares it with direct soil propagation using rooting hormones. We’ll also examine the differences between liquid and powdered rooting hormones to help you make informed choices for successful plant propagation.

What is a Cutting?

Cuttings are an asexual way of producing plants. Another way of putting that is the plant is ‘cloned’, i.e. what you are growing will be a replica of the parent plant without any other genetic material that will change how it grows or what it produces. A cutting from the ‘White Marseille’ fig will grow into a ‘White Marseille’ fig, with a growth habit and fruit that is exactly the same as the tree it was cut from.

I have seen people lop off 3ft branches from a tree and call them a cutting, but whilst I admire their confidence, that’s not really a cutting. Although there are some differences in the width and length of cuttings, they are generally 6-9” and have three nodes. A node is the bumpy bit on a stem or branch that leaves grow from, and it’s important to know this because roots usually grow from a node.

Fully lignified, mainly tip cuttings from a fig tree. Each is approximately 8” long with at least three nodes. Photo by Judith Paul

Some plants, often ‘woody’ plants like Mulberry trees (Morus), can also grow roots from what are called lenticels. Lenticels are naturally occurring, raised, and often lens-shaped pores in the bark that facilitate the exchange of oxygen and carbon dioxide between the internal tissues and the atmosphere. The areas where new roots form on a stem cutting can, in some plant species, originate in the vicinity of these lenticels, as they are areas of loosely arranged cells that can be encouraged to form roots with the right environmental conditions.

Prominent lenticels noticeable on Mulberry (Morus), and a leaf growing from a node. Photo by Judith Paul.

Knowing where roots are likely to develop on a cutting is part of the puzzle to successfully growing viable plants using this type of propagation.

What is Water Rooting?

Water rooting is a propagation method where plant cuttings are immersed in water to encourage root development before transplanting into soil. This technique is commonly used for many houseplants and some outdoor species, including pothos, philodendron, mint, impatiens, coleus, and even some woody plants such as figs and hydrangea. These types of plants do not need much (if any) callusing to produce roots, which is handy because callusing cannot form in water. Gardeners simply snip a healthy stem, remove lower leaves, and place the cutting in a jar or glass of clean water, ensuring that the parts of the cutting from which the roots form are submerged.

Roots developing on some curly willow cuttings, Salix matsudana 'Scarlet Curls' that had been ‘stored’ in water before being ‘stuck’ in soil. Photo by Judith Paul.

Advantages of Water Rooting

• Visual Monitoring: One of the greatest benefits of water rooting is the ability to observe root development. Transparent containers allow gardeners to track progress, spot healthy roots, and identify issues like rot or stagnation early.

Significant root development easily monitored on these Salix Matsudana ‘Scarlet Curls’ cuttings. The roots look good, but they’re pretty much useless. Photo by Judith Paul.

• Ease of Use: Water rooting requires minimal equipment and setup. Just a container and tap or distilled water are enough to get started, making it ideal for beginners or those without access to specialized supplies.

• Low Risk of Desiccation: Since the cutting is immersed in water, there is almost no risk of it drying out, which can be a problem with soil propagation, especially in dry environments and irregular watering.

• Fast Root Growth for Some Plants: Many soft-stemmed plants root rapidly in water, sometimes developing roots within days to weeks. This quick turnaround is appealing to impatient gardeners, but it has some drawbacks!

Disadvantages of Water Rooting

• Weak Root Structure: Roots formed in water can be thin, fragile, and not adapted to soil conditions. When transplanted, these water roots may struggle to adjust, leading to transplant shock, delayed development, or even total failure.

These water roots on Salix matsudana ‘Scarlet Curls’ are very fragile and have no root hairs, which are the feather-like, delicate parts of roots that absorb water and nutrients. Although abundant, the roots in the picture are pretty much useless in their present state, but they do have the ability to grow root hairs if appropriately cared for once they’re in soil. Photo by Judith Paul.

• Limited Species Suitability: Not all plants root well in water. Woody stems and certain ornamentals may rot or fail to develop roots, making water rooting unsuitable for many types of plants.

• Risk of Rot and Disease: Standing water can become a breeding ground for pathogens. Without regular water changes, cuttings may rot before they root.

• Transition Challenges: Moving water-rooted cuttings to soil can be tricky because it can take three days for the roots to ‘learn’ that they are in soil and become capable of absorbing moisture and nutrients. The sudden change in environment often stresses the plant, sometimes resulting in wilting, leaf drop, or slow growth until soil-adapted roots form.

Water roots can be fiddly to pot up because of their fragility. Note the angle at which the potting mix is in the container, and how the water roots are placed on the angled substrate. Photo by Judith Paul.

• Callusing: Protects against disease and rot, reduces water loss, and shortens the time needed for propagation. It is a natural healing process where the wound is sealed, similar to a scab on a human wound, making the cutting more likely to successfully grow roots. Some types of plants need to have their cut ends callused over for roots to form, but callusing does not form in water. Trying to get succulents or cacti to grow roots when their cut end is submerged in water is going to fail. 

Soil-based Propagation with Rooting Hormone

In contrast to water rooting, many gardeners prefer to stick cuttings straight into soil, and sometimes this is done with the help of rooting hormone. Soil-based cuttings is a technique that mimics natural conditions, encouraging cuttings to develop roots adapted to garden life from the outset. Many plant species, such as hydrangea and euonymus, do not need rooting hormone, just favorable conditions. This makes the process even simpler!

Roots developing on cuttings from the Dappled Willow, Salix integra ‘Hakuro-nishiki’ with the presence of root hairs clearly visible. This photo was taken approximately 8 weeks after being ‘stuck’ into potting mix. No hormone used. Photo by Judith Paul.

Advantages of Soil-Based Rooting

• Direct Adaptation: Roots formed in soil tend to be stronger and better suited for plant growth after transplanting. The risk of transplant shock is lower because roots don’t need to adjust to a drastically different environment. With little or no setbacks, plant development is often quicker.

• Wider Applicability: Soil propagation works well for a broader range of plants, including woody shrubs, trees, and difficult-to-root perennials.

• Reduced Rot Risk: Good soil drainage and aeration reduce the likelihood of rot compared to standing water.

• Use of Rooting Hormone: Applying rooting hormone boosts the chances of successful rooting, especially for challenging species. Dry rooting hormone products are readily available, whereas those suitable for rooting plants in water are more difficult to come by.

A nice little Dappled Willow starter plant ready for sale. Started in potting mix approximately 8 weeks before this photo was taken. Photo by Judith Paul.

Disadvantages of Soil-Based Rooting

• Limited Visibility: One major drawback is that monitoring root development is difficult because the roots are hidden within the soil. Monitoring relies on inspecting top growth (if any – this depends on the time of year the cutting was started) and inspection of the stem. Even then, observations can be misleading, with green stems not producing roots and the presence of foliage not necessarily indicating equivalent development of roots.

• Moisture Management: Soil-based propagation requires careful moisture management; too much water can lead to rot, while too little may cause the cuttings (and any emerging roots) to dry out before roots are properly formed. Having the right type of substrate for the species being propagated can make the difference between rotted cuttings and rooted cuttings.

This is a 50/50 peat and perlite mix (volume, not weight). It is suitable for a wide range of plants, but it is not suitable for those that do better in a free-draining mix like construction sand. Photo by Judith Paul.

• ‘Clean’ Soil: Soil-borne pathogens and pests can pose a threat to vulnerable cuttings, especially if the soil contains these or develops them because of poor drainage. Others may be sensitive to pH levels within the substrate, e.g. cuttings from an acid-loving plant such as camellia may not produce roots in a compost substrate. Using soil that has been dug out of the garden may work, but is not recommended as the best option.

• Timing: Soil propagation can be slower than water rooting, particularly if environmental conditions are not optimal or if the cuttings are sensitive to transplant shock. 

• Transitioning: Timing cuttings to be at the right stage for acclimating into its next size container or forever home is an important factor. Transplanting a rooted cutting into its garden setting in the middle of summer is not ideal, and unlikely to be successful unless you have the time and inclination to helicopter parent it until it is established.

• Research and Experience: Some plants, such as lilacs and crepe myrtles, need warmth to push out roots and are best started from late spring to early fall. Others are best done as hardwood cuttings from late fall to late winter, e.g. forsythia and arborvitae. Local climate, misting systems, shade, heating mats, grow lights, and many other factors all contribute to successfully getting roots on cuttings and growing those on into viable plants for transitioning to the garden.

• Substrate Selection: Experience and research may also provide you with the information needed to select a substrate that best suits the type of plant (and cutting) that is most likely to be successful. For example, some cuttings do better in free-draining construction sand than in a 50/50 peat and perlite mix.

Construction Sand

River Sand

Very fine sand, such as that sold for playgrounds, is adequate, but for growing roots on cuttings, sand that contains small pebbles and bits of gravel has better drainage.

• Next Step Planning: For hobbyists and home growers, selecting containers and rooting hormones can be a consideration of lesser importance than it is for commercial growers. If a rooted cutting is going into your own garden, the type of container it was started in is almost irrelevant, provided it worked! For a commercial grower, planning a smooth transition from an unrooted cutting to a sellable plant in the most cost-effective way is critical for running a profitable business.  

Comparing Water Rooting to Soil Propagation

LHS – water roots at 6 weeks. Very little foliage, and the roots are not even touching the sides of the cup. RHS – stuck straight into soil 8 weeks before photo taken (no hormones). Significant foliage is developing, including the start of branching, and the roots are filling the cup.  The plant on the LHS that was started in water is developmentally delayed and will take months to catch up with the plant on the RHS. Photo by Judith Paul

Conclusion

Water rooting remains a favorite for its simplicity, visual appeal, and accessibility. However, it’s not suitable for all plants, and water-rooted cuttings may face challenges when moved to soil. Soil propagation with rooting hormone offers broader compatibility and stronger root systems, although it requires more attention and materials. Rooting hormones - liquid or powdered - are powerful tools for boosting success rates, particularly for difficult or woody cuttings, but those that are commercially available are mainly designed for use with soil-based cuttings. By understanding the strengths and limitations of each technique, gardeners can select the best propagation method for their plants, ensuring vigorous growth and thriving collections.

---

Article by Judith Paul

Hi, I'm Judith Paul, with a gardening style best described as “Oooo, there’s a gap over here!” My work history is equally unpredictable (possibly even quirky) and ranges from pulling eel-infested cow carcasses out of creeks to managing multi-million-dollar projects across various industries. I’m a Kiwi (referring to the iconic flightless bird of NZ, not the fruit) who has also lived in Australia. Currently, I run a licensed and inspected plant propagation nursery in North Carolina (USA) when I’m not teaching, writing, or editing.

---