Propagation of Deciduous Azaleas
The following article by Esther Berry of Aberdeen, Wash., appeared in the May 1993 issues of the Seattle Chapter newsletter. Esther Berry is an ARS Gold Medal recipient.
I like to take the cuttings just as early as they are large enough to stick. It seems to be useful to cut so as to retain a small sliver of the old wood on the base of the cutting. Of course, this is possible only if the cutting is still small enough to use (2-3 inches). I leave no more than three leaves. The heel of the old wood is not absolutely necessary, but if the subject is known to be difficult, it could make a difference.
Now that we have Benlate, I sterilize all cuttings by soaking them a half hour in a solution of 1 tablespoon of Benlate to 2 gallons of water. However, when I did most of my propagating, we didn't have Benlate and I used 1 tablespoon of Purex in 1 gallon of water, if I used anything at all. Under constant mist, I doubt that it is necessary to use anything at all.
I put the rooting compost in a flat and stick the cuttings in that, rather than to put them directly in the bench. In this way, I can move them about as needed. Under constant mist, I use half peat moss and half perlite for the rooting compost because I think that a little more drainage is necessary. Under usual greenhouse conditions I would use three parts peat to two parts perlite.
If the cuttings are quite soft, I use a #2 Hormodin powder for the growth auxin. If they are a little firm, then I use the #3 Hormodin.
I put the flats in a cold frame in full sunlight. There is a soil cable set at 65-70°F for bottom heat and Monarch fogger mist nozzles suspended above the frame. There is no timer on the foggers. I just turn them on in the morning and off at night.
After about two months or so, when I believe the cuttings to be rooted, I close the frame and shade it on very bright days. I water usually every other day. As the weather becomes cool in the fall, I set the thermostat at just above freezing and let them sit through the winter. I think it is important that the cuttings not be lifted until they have gone into growth the following spring.