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["rooting" <rooting@hortus.com>]

reply to Chris Mauchline where he says
"I have two cuttings of apple that I intended to graft.  The cuttings have had other ideas.  They've started to push growth and they've callused.  I intend to pot them up and try to root them.  Would rooting hormone on already callused tissue be beneficial or harmful? 

I have 1% NAA, 1% IBA, 8% IBA, All in powder form.

I haven't had good luck with NAA.  I was thinking of using 1% IBA on one cutting and 8% on the other.  Any experience, knowledge that would contradict this?" 

 

There are several issues to address:

If Chris you only have two cuttings you are better to have a good yield if you do your grafting now. If your intent is to trial plant rooting hormones then you should be trials with a larger number of cuttings. malus is difficult to root and the possibility of two cuttings rooting is low.

 

Then, you have three products at hand. NAA in 1% powder form is quite unusual. The only commercially produced product that we know of with NAA in dry powder form is Rhizopon B which is only made in %0.1 and %0.2. It is only available in Holland and perhaps some local European countries for specialty crops such as carpinus (hornbeam), but even then it is rarely used and there are better choices.

 

For IBA containing material there is a better choice. Most commercial growers prefer to use solutions, such as IBA Water Soluble Salts and Rhizopon AA Water Soluble Tablets. For dry powders Hormex and Hormodin and Rhizopon AA #3 (0.8% IBA) are all available in the concentration range 0.8% to 1.0%. There is not much difference in performance between the concentrations, though 0.8% is 'more' universal.

(sources: http://hummert.com or www.carlinsales.com or http://www.fredgloeckner.com ).

 

Regarding malus propagation, the observations by Chris are correct. However, the callus and 'flush' are not indications of root formation. Callus formation is the plants defense against entry of pathogens by closing an open wound, much the way that skin forms over an open cut. There are other actions relating to the callus formation which causes root formation near the marginal edge ... but the callus is not a need indication of for root formation going on. The flush that was observed is typical of winter cuttings. Cuttings for spring flowering planting plants are often 'forced' to produce florist crops such as forsythia and flowering cherry. This again is no indication of root formation only that the cutting is not dead.

 

ROOTING OF MALUS

 

Malus cuttings should be taken from the current seasons growth, 6-8 inches long, about the diameter of a pencil, from near to the base of the tree not the top of the tree.

 

For winter cuttings taken November-December use a long soak method:

http://rooting-hormones.com/IBAmethd.htm#IBAImmersion

Immersion Method.
Immerse the basal end of cuttings approx. 1" in the solution 4-12 hrs. Plant the cuttings immediately. Use on cuttings which are more difficult to root or are more woody. A long soak of the cuttings in a low concentration solution causes the plant tissues to absorb the active ingredients. Use this method on plants which may be sensitive to high concentration used in Quick Dip.
Herbaceous and Woody Cuttings, including hard to root cuttings and rootstocks: 50-150 ppm IBA (Rhizopon AA Water Soluble tablets @ 1-3 tablets per liter of water) or use IBA Water Soluble Salts at that rate. http://www.rooting-hormones.com/IBAsalts.htm .

 

For spring cuttings May-July use the dry dip method with a rooting hormone concentration 0.8% IBA:

http://www.rooting-hormones.com/drydip.htm

The Dry Dip Method.
    * Take plant cuttings, usually stem, root or leaf cuttings.
    * Woody cuttings are usually wounded by making a 3/4" notch at the basal end. Herbaceous cuttings are not wounded.
    * From the stock container of Rhizopon AA dry powder take off enough powder for one time use.
    * Do not contaminate the stock container of powder by returning the used portion to the container.
    * Dispose of the used portion.
The Dry Dip Method the basal end of the cuttings 3/4 to 1 inch into the powder, one by one or in small bundles. Make sure that the powder is evenly distributed in a thin even layer (1/32 to 1/16 inch) over the whole base of the cutting. Too much powder on the cuttings might result in excessive rooting where there is surplus powder. Root formation can be expected all over the part of the cutting covered with the powder. Avoid contact between the powder and foliage and other over ground parts of the stem since it may cause phyto toxicity. Tap off the excess powder. Plant the cuttings immediately in moist media. After treating cuttings take care of them.