Techniques of Propagation by Cuttings Cutting treatments – Wounding Root production on stem cuttings can be promoted by wounding the base of the cutting. This has proved useful in a number of species, such as juniper, arborvitae, rhododendron, maple, magnolia, and holly.

A potato peeler (arrow) is used for wounding rhododendron cuttings— part of the leaf surface area has been removed by the pruning shears.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Wounding Wounding a cutting with a knife—notice the thumb protection for the propagator.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Wounding Tool designed for making wounding cuts in the base of cuttings to stimulate rooting. Four sharp prongs make the actual cuts as the cutting is pulled through the opening.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Wounding

Wounding the basal side of a magnolia cutting with pruners.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Stripping Basal Leaves The benefits of stripping basal leaves is species-dependent; Berberis and Juniperus cuttings benefit, whereas Spiraea, Forsythia, and Weigela do not. Stripping basal leaves of cuttings reduces the propagation bench space required, allows the propagator more flexibility to work with different size propagules, and may serve to improve the contact area between the cutting and media.

Preparing a Thuja cutting by stripping off the lower needles.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin Treating cuttings with auxin increases the percentage of cuttings that form roots, hastens root initiation, and increases uniformity of rooting. The most commonly used auxins are: indole-3-butyric acid (IBA) α-naphthaleneacetic acid (NAA) and the potassium salt of IBA (K-IBA).

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin

Auxin concentration is calculated in either Parts per million (ppm) Percentage Molarity

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin

Auxin preparations should be stored in a cool, dark place – refrigeration. Color coding with food dye or colored containers can help denote different concentrations.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin

Commercial auxin quick dip preparations are sold as concentrated solutions (stock solutions). These must be diluted to make your desired concentration.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin They may indicate their concentration based on percentage or ppm. A one percent solution = 10,000 ppm. One part per million is equal to 1 mg per liter. Talc preparations are sold in various concentrations and not meant to be diluted. Their concentrations are based on percentages.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin

A typical auxin formulation might have 1% IBA. This would be 10,000 ppm. That equals 10,000 mg per liter or 10 grams per liter.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin PPM of concentrate x Volume to be removed from concentrate = Desired PPM of new solution x Volume needed for the new solution. Make a 1 liter solution containing 250 ppm IBA from an auxin concentrate that contains 1% IBA. 1. Solve for volume

10,000 ppm X Vol (ml) = 250 ppm X 1000 ml

2. Divide both sides by 10,000 ppm

Vol (ml) = 250 ppm X 1000 ml / 10,000 ppm

3. Multiply 250 ppm by 1000 ml

Vol (ml) = 250,000 ppm ml / 10,000 ppm

4. Divide by 10,000 ppm

Vol (ml) = 250,000 ppm ml / 10,000 ppm

5. Add 25 ml of concentrate to 1 liter Vol (ml) = 25 ml

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin In the scientific literature, auxin concentrations are reported in molarity. One mole is equal to the molecular weight of the compound in grams dissolved in one liter of solvent. It is used because it gives you the number of active molecules regardless of the weight of the compound.

Different auxins have different molecular weights. Therefore, a 1000 ppm solution of IAA and IBA would have a different number of active molecules in the solution, but 100 micromolar solutions of IAA and IBA have the same number of active molecules. Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin Since commercial auxin concentrations are reported in percentage or ppm, you need to be able to convert ppm to molar. ppm = micromolar x molecular weight divided by 1000. x ppm = 2000 M IBA x 203 / 1000 = 406 ppm Micromolar = (ppm x 1000) divided by molecular weight. x M IBA = 406 ppm x 1000 / 203 = 2000 M IBA

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin

Use 500 to 1,250 ppm for easy-to-root herbaceous cuttings. Use 500 to 3,000 ppm for easy-to-root woody cuttings. Use up to 10,000 ppm for difficult-to-root woody cuttings.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin Auxin application methods 1. Dilute soak 2. Quick dip 3. Talc 4. Spray

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin The dilute soak method is an older procedure where the basal part of the cutting is placed in the auxin solution. Timing – up to 24 hours.

Concentration – 50 to 150 ppm. Solution type – must be in water. Effectiveness – works well but is cumbersome because of timing.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin The quick dip method is a common treatment. The base of the cutting is immersed in the solution. Timing – 3 to 5 seconds. Concentration – 500 to 10,000 ppm. Solution type – usually 50% solvent (ethanol). Potassium salts in water. Effectiveness – most effective and uniform way to treat cuttings. Some cuttings may be sensitive to solvent. Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin This automated system was developed to treat many cuttings at a single time and to recycle the auxin solution.

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin The talc (powder) method is also a common treatment. The base of the cutting is coated with the auxin talc.

Concentration – 0.1 to 8.0%. Carrier – talc is the most common. Effectiveness – an effective treatment, especially for herbaceous cuttings. Sometimes it is beneficial to wet cuttings to get talc to adhere. A pre-dip in a solvent (ethanol) may increase effectiveness. Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin The spray method uses an atomizer to spray the foliage. Timing – until the solution drips from the leaves. Concentration – 500 to 5,000 ppm. Solution type – usually the potassium salt of IBA in water. Effectiveness – varies by species, but when effective it reduces worker exposure and labor time. Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin Auxin and rooting in mum cuttings

Treatment

Duration

Untreated Quick dip Dilute soak

Roots per cutting 19.7

1 seconds

41.3

3 seconds

40.5

8 hours

40.4

16 hours

42.0

Talc

29.5

Spray

38.2

Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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Techniques of Propagation by Cuttings Cutting treatments – Auxin Auxin and rooting in mum cuttings

Untreated

100 ppm

250 ppm

500 ppm

IBA concentration Hartmann and Kester’s Plant Propagation, Principles and Practices 8th ed. Hudson Hartmann, Dale Kester, Fred Davies, Jr. and Robert Geneve

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