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An old, dear friend of mine, Sid Burns, taught me how to make my own rhododendron rooting hormone.  I normally use a 2% IBA hormone and these instructions are for that concentration.  On some cultivars I use 1% and on others 4%.  These two can be made by altering the amounts of the ingredients.  I might add that this 2% hormone works for many woody plants: Ilex (holly, English, American and Japanese), junipers, some dwarf conifers and many other plants that don’t come to mind right now.

2% IBA rooting hormone:

5 grams indolebutyric acid  (IBA)

1 ½  cup 100 proof vodka

250 grams talc (or 240 grams talc and 10 grams Benlate)

IBA is soluble in alcohol, but using denatured alcohol that is sold in hardware stores has denaturing agents in it that seem to ruin the IBA, so we use 100 proof vodka which is 50% water and 50% grain alcohol.  The IBA is placed in a jar with a screw top along with the vodka.  I use an empty peanut butter jar, about 7” high and 3” in diameter.

It will take several days for the IBA to dissolve in the vodka.  Shake the jar as much as you want and be patient.  It will eventually dissolve.

After the IBA is completely dissolved add the talc or talc and Benlate mixture.  Shake the jar or somehow mix the thick material to be sure that all the talc is wet. It will be very thick.  Pour it out on a piece of glass and spread it out in a thin layer and leave it in a dark place to allow the vodka to evaporate.  It will take several days.  Scrape up the now dry material with a paint scraper or putty knife and put it into a jar.  Shake the jar vigorously to turn the hormone into a powder.  Store it in a sealed jar in the refrigerator.  It will last for years.

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