Horticulture 202        Plant Propagation

Introduction:

 

Lilac bushes (genus Syringa) are very popular

landscaping plants found in the United States.

They are best known for their beautiful purple

or white flowers that produce a very strong and

pleasant smelling scent that can travel great

distances.  Anyone living in USDA zones 3

through 5 can enjoy these beautiful spring

blooms.  These plants have been a part of the

United States landscape since the 1750s. 

Lilacs were grown in the first American

botanical gardens and early presidents, George

Washington and Thomas Jefferson, grew these

plants in their home landscapes as well.  Lilacs

are very versatile plants and can be used for

many purposes.  Due to the vast amount of

cultivars that exist, there is a huge variety to

choose from, giving homeowners many options to explore.  Lilacs are also ideal plants for the typical homeowner or gardener as they do not require much maintenance and are resistant to many environmental stressors.  It is important to note, however, that lilacs are not fond of prolonged wet conditions.  Therefore, they should be planted in areas that drain readily.

 

 

 

Propagation:

 

Methods:

 

There are several methods that one could utilize to successfully propagate lilac cultivars.  These include both sexual and asexual (sometimes referred to as vegetative) propagation techniques.  Sexual propagation, which is utilized via seeds, is usually not recommended for lilac propagation.  The main reason is that specific genes that give lilac cultivars their desired traits can be lost through genetic recombination that occurs as seeds are produced.  Also, growing lilac bushes by seed takes time, and one usually must wait 3-4 years before the plants are mature and produce flowers.  As a result, the most common propagation methods involve asexual reproduction.  Genes will be preserved, and the plants will reach maturity in a shorter amount of time.  Types of asexual propagation that can be used are cuttings, grafting, tissue culture, and ground layering.  However, the most common is cuttings.  This is due to the fact that grafting usually requires more work and is very complicated, and tissue culture requires special equipment that the typical consumer usually does not have.  Ground layering, even though it is much easier than grafting and tissue culture, is also not normally used due to the fact that only a small number of plants can be obtained from the process.  By using softwood cuttings, any homeowner or gardener can easily reproduce many new lilac bushes for their enjoyment.

 

 

Step by Step Procedure for Stem Cutting Propagation:

 

Cutting Preparation:

 

1. Start with a plant that is healthy, in good condition, and lacks disease and pest problems.  This ensures that the cuttings taken will be healthy and will root successfully.

2. Locate the cuttings on the plant.  The cuttings need to be of the softwood type.  To ensure that cuttings are of the right type of wood, the cuttings should consist of only the new, green growth that appears at the start of the growing season.  It is also important to only take terminal cuttings (820).

3. Prepare your cutting media and add it to the containers that the cuttings will be placed in.  The media should have good water holding capacity and aeration.  It must also be disease and pest free.  A mixture of sterilized potting soil with some added sand and perlite should satisfy these requirements.  Also be sure to poke drainage holes in the bottom of your containers if they do not have any.

4. Disinfect the knife, scissors, or garden snips that will be used to cut the plant material.  If not properly disinfected, diseases could infect the cuttings and the parent plant.  Washing the tool with hot, soapy water should be enough.

5. Rooting hormone, specifically auxin, will be needed to initiate rooting in lilac cuttings.  Be sure to have some ready when cuttings are to be taken.  This can be easily acquired from Walmart, a local gardening store, or a local nursery.  The concentration depends on the exact species and cultivar.  However, most do best when the concentration is 3,000 ppm IBA (indole-3-butyric acid) (820).  Talc powder products that say 0.3 % IBA on the labels (such as Hormodin 2) will have the right concentration and are generally recommended over dip treatments for lilac propagation. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Taking the Cuttings:

 

1. Timing is critical.  Using your disinfected tool, take the terminal, new growth cuttings once the shoots have grown to 4-6 inches in length with 2-3 nodes on the stem.  The nodes are where the leaves attach to the stem.  Only take cuttings in the early morning, around sunrise, when plants are turgid and have not experienced the stress the upcoming day will bring.

2. When taking cuttings, always take a few more than needed.  This ensures that if one or two do not root, then there will be extra ones available to take the place of any that failed.

3. After taking the cuttings from the parent plant, remove the leaves from the stem.  However, do not remove the top 2-3 leaves.  These provide carbohydrates to the cutting via photosynthesis.

4. If these top leaves are large, cut them in half.  This will prevent excess transpiration which can lead to the desiccation and death of the cutting.

5. Dip the cut end of the cuttings into water briefly to wet them.  Then dip the bottom inch of these ends immediately into the rooting hormone mentioned earlier.

6. Put the cuttings, cut side down, into the media that was made earlier.  Be sure to space them out.  Try to do this immediately after taking the cuttings as they will begin to dry out and desiccate.  If this cannot be done immediately, place the cuttings into a plastic bag, and place them in the refrigerator set to about 40˚F (40). 

7.  After placing the cuttings in the media, thoroughly soak the media with water.

8. Cover the cuttings with a plastic bag and seal it shut.  This will simulate a humid environment that is found in greenhouses.  As a result, the cuttings will not dry out as easily and have a better chance of rooting.  If you own a residential greenhouse, use it instead.

9. Place the cuttings that are now in their containers onto a warm surface to supply bottom heat.  The media should be warmed to about 75˚F (40).  A heating pad can help accomplish this task.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Caring For Cuttings:

 

1. Water the cuttings frequently to keep the media moist and prevent desiccation.  However, do not waterlog the media as this could lead to disease problems.  Be sure to allow water to easily drain from the containers after watering.  This will prevent disease problems.

2. Open the plastic bag occasionally for several minutes to provide aeration to the cuttings.  This prevents disease problems.  Poking small holes in the bag is an alternative option, however, cuttings will be at a greater risk for desiccation.

3. Provide cuttings with access to light, however, be sure that the light is not too intense, as it will dry out the cuttings.  Misting the leaves while watering can reduce this risk.

4. Cuttings will normally take 3-7 weeks to root.  If new growth can be seen, then that is usually a good sign that the cutting has rooted.

5. Cuttings that do not root and die should be removed immediately as they can serve as vectors of disease (42).  Do not discouraged if a small handful of the cuttings die.  Even if everything is done correctly, a few lilac cuttings still will not root.

 

 

Transferring Cuttings:

 

1. Cuttings must be hardened off so that they can survive in less humid conditions when moved to larger containers.

2. Once roots are well established, gradually cut back on watering and leave the cuttings uncovered for longer periods of time (42).

3. Continue to do this for several days to one week (42).  Once complete, you may transfer them to larger containers.

4. Care for these new plants like any other plant.

5. Congratulations!  You now have new lilac bushes for your gardens!

 

 

 

Conclusion:

 

Lilac bushes are beautiful deciduous shrubs that will put on pretty displays each spring year after year.  These plants are very tolerable of many conditions and are perfect for any home landscapes due to this resiliency.  Lilac bushes can also be propagated fairly easily through cuttings as well.  With thousands of cultivars to choose from, the true challenge presented by lilac bushes is deciding which cultivars you want in your landscape.  For more information, please feel free to explore the references listed below in the next section.

 

 

 

References:

 

Bruins, Elizabeth. “Propagation of French Hybrid Lilac (Syringa Vulgaris cvs.).” North Dakota State University. Web. N.d. Retrieved from: https://www.ndsu.edu/pubweb/chiwonlee/plsc368/student/papers04/elizabethbruins/syringa.htm.  Accessed on Feb. 28, 2016.

 

Dyer, Mary H. “Propagating Lilac Bushes: Growing Lilac From Cuttings.” Gardening Know How. Gardening Know How, LLC. Web. Retrieved From: http://www.burncoose.co.uk/site/page.cfm?page_ref=how_to_care_for_hydrangeas#.  Accessed on Feb. 28, 2016.

 

Fordham, Alfred J. “Propagation and Care of Lilacs.” The Arnold Arboretum of Harvard University. N.d. Pages 40-42. Print.  Retrieved from: http://arnoldia.arboretum.harvard.edu/pdf/articles/1543.pdf.  Accessed on Feb. 28, 2016.

 

Hartmann, Hudson T., Dale E. Kester, Fred T. Davies, and Rovert L. Geneve. Hartmann & Kester’s Plant Propagation: Principles and Practices. 8th ed. Boston: Prentice Hall, 2011. Page 820. Print.

 

 “Plant Propagation Laboratory Introduction and Exercise.” Institute of Food and Agricultural Sciences.  University of Florida.  Retrieved from: http://irrecenvhort.ifas.ufl.edu/Propagation/labs/module3/rooting_hormones.pdf. Accessed on Feb. 28, 2016.