If you have ever wondered what is the best way to propagate geraniums, then this article is for you.

 

Overview:

• This summer I started an experiment to determine what was the best way to propagate geranium plants (AKA pelargonium species).
• The results were surprising and they will definitely change the way I do things in the future.
• If you want to skip to the punchline regarding the best propagation method, just read the only underlined sentence found toward the end of this article.  However, the “Materials & Methods section of this article is basically a road map to successfully do it yourself.  Yea, a way to get more free plants!

 

Why bother you ask?

Well… a little while back I tried to research the best way to propagate geranium plants.  As it turns out, there are a lot of different techniques, and everyone seems to think that their method is the best.  So, this left me in a bit of a dilemma; how do I move forward with this conflicting information?  Besides, I thought to myself, how can there be 20 BEST ways to do something?  Another interesting point is that I have not found any “proof” to support that one particular propagation technique is scientifically better than another person’s “best” method.

As a result, I set up an experiment to answer the question for myself.  I tested the top few methods on my list and I also added another crazy method in there just for fun.  I did my best to control the experiment for outside variables so the results could be as clean as possible.  For example, I used the same soil, growing conditions, and the same mother plant for all of the cuttings.

 

Materials & Methods:

Plant preparation:

• On July 12, 2014, I collected a small pile of cuttings from a single geranium plant (Ivy-leaved geranium: Pelargonium peltatum).
• Multiple softwood cuttings were then all clipped to about the same length (about 5 in or 13 cm long).
• Old woody stems were discarded because of lower expected germination rate with woody stems.
• The bottom leaves were removed from all of the cuttings.  This left only a few leaves at the top of each 5 inch long cutting.

 

Soil preparation:

• The soil mixture that I used was native sandy soil mixed with about an equal amount of grow mulch.
• I thoroughly mixed up the soil in a large bin separately, and then added equal amounts of the soil-mix into each of the five containers.
• In each container, I made 5 depressions in the soil for the cuttings to be placed into.  The pattern for the 5 depressions was the same that you would see on a dice (die).
• The depressions in the soil for the cuttings were about 1 inch deep.  These soil depressions were made with the non-writing end of an old clean sharpie pen.

 

Different propagation methods tested:

The main variable between the five propagation methods tested was the material that was added to the soil-end of the cutting.  The five arms of the experiment are as follows.

1. Control (nothing was added to the end of the cutting)
2. Root hormone (the powdered stuff you can get at the store)
3. Honey (apparently honey is beneficial because of it’s antibacterial properties)
4. Tanglefoot  (yes it was a crazy-unsupported idea)
5. Clean water (the cuttings were just placed into regular old water with no additional prep)

 

All containers got the same treatment:

• The specific material being tested (honey, root hormone, Tanglefoot) was added to the soil-end of the plant-cutting.
• Five cuttings (for each separate arm of the experiment) were added to the pre-made soil depressions in each container.
• Then the soil was pushed around the cuttings and watered in (obviously except for the last option where the 5 cuttings were just put in water).
• The containers were all placed in the same physical location in the yard. This location was was partly shady.
• Every few weeks, I moved the containers around in relationship to each other to be extra sure they were all getting the same treatment.

 

Result journal:

July 26, 2014

• All of the cuttings looked about the same.
• All cuttings appear to be struggling a bit and leaves were turning yellow-ish.
• Perhaps this early yellowing reflects the changes from diverting energy into the roots, and/or I am over watering.

 

August:

• No idea where I was.
• I must have been too busy to take pictures or keep notes-sorry.

 

September 4, 2014

The results below are ordered in relationship to the propagation success:

1. Control: 4/5 cuttings survived and total/overall growth for this technique was the most robust.
2. Honey: 4/5 cuttings survived and total vegetative growth lagging behind the control.
3. Root hormone: 3/5 cuttings survived
4. Water: 2.5/5 cuttings survived (I say 2.5 because one of the remaining cuttings still has some leaves on it but the stem is rotting. Another cutting is not rotting but has no roots. Only one cutting has roots.
5. Tanglefoot: 1/5 cuttings survived.

 

 September 18, 2014 

The results below are ordered in relationship to the propagation success:

1. Control: 4/5 cuttings survived and total growth was the most robust. Cuttings are even flowering!
2. Honey: 4/5 cuttings survived and total vegetative growth lagging behind the control.
3. Root hormone: 2/5 cuttings survived (Another cutting dead from Sep 4).
4. Water: 2/5 cuttings survived.
5. Tanglefoot: 1/5 cuttings survived.

October:

• Sorry no pics.
• However, the results for October are about the same as Sept 18 except that all of the cuttings in the water part of the experiment are now dead.

 

Conclusion:

1. In this experiment, the simple control method did the best!  Just stick the cutting in soil and keep moist. This was actually a big surprise for me.
2. The honey experiment option was close behind at second best.  The honey had the same number of cuttings surviving, but the growth rate was not as robust as the control method.
3. In this experiment, the use of root hormone was no more than an added expense that actually lead to worse results (when compared to the control method).
4. The Tanglefoot option was a disaster and is not recommended for this indication.  Only one sickly looking cutting survived in this arm of the experiment. (Note, this is not the intended use of Tanglefoot which I think is an awesome product for sap-sucking bug control).
5. Rooting in water was not very successful at all.  Only one of the five cuttings ever rooted and it eventually died as well.  In fairness, I should have transferred the rooted cutting into soil earlier.  However, even if I did – and it survived, it still would mean that only 1 out of 5 in the water propagation method cuttings could have lived.

 

Some additional interesting info about Geraniums:

• Geraniums (pelargonium species) are a beautiful and hassle free option for drought tolerant landscaping in Southern California.
• Geraniums are also in the elite category of gopher resistant plants. However, they but not totally gopher proof.  For more details on that subject, see my earlier article on Gopher Resistant Plants: Truth & Fiction.
• They are evergreen perennials that are both drought and heat tolerant. However, they can only tolerate minor frosts.
• Geraniums are indigenous to Southern Africa