Mike Creel, who gardens in Lexington, South Carolina, has been developing and refining a natural approach to propagation for a number of years. His simple, low-tech approach has been working for him and others on a wide variety of woody plants—outdoors, without a greenhouse. The principal features of Mike’s approach to rooting cuttings are:
• drilling more holes in the pots for better drainage;
• filling the pots only half full with quick-draining media;
• topping the media with a sprinkling of humus fines from around a local plant of the same species being propagated;
• wounding and sticking mature woody cuttings (not new growth) into the dry media, with no hormones;
• fitting the pots with “mini-greenhouse” domes made of recycled plastic bottles, large enough to cover the cuttings yet small enough to admit water between the domes and the pots;
• placing the pots off the ground (hung or put on perches) to avoid earthworm invasion, and protecting them by 65% shadecloth from full sun;
• watering the pots thoroughly after placing them, and then as needed to total one inch per week; and
• letting nature do the rest, by disturbing the pots as little as possible.
This Creel-Way approach works throughout the year, using either dormant cuttings (preferred) or cuttings in active growth. Mike has also developed a similarly natural approach to propagating seed outdoors.
You can download detailed notes and pictures from Mike’s July 21 presentation to the 2005 Native Plant Conference, Cullowhee NC, and read them offline. Propagating WITH Nature: Simpler Is Better (732 KB PDF file)
Earl Sommerville, who gardens in Marietta, Georgia, has provided information about a new approach to rooting deciduous azaleas, in the form of a research paper and a handwritten note. It’s easy to do and it works for him. Earl introduced these papers as:
“About a year ago I took up Tissue Culture and met Dr Paul Read, a professor at The University of Nebraska. He was very interested that I would like to study Tissue Culture being that I was over seventy years old; he took it upon himself to help me.
Within a few weeks I received a number of studies that were relevant to Native Azaleas and other studies that were good background material.
The one study that is most interesting is called “Novel Methods in Micropropagation“. The focus of this paper is on forcing softwood shoots from large stem segments, to be used in tissue culture and vegetative propagation. This is a very low-tech method and most every one can do this.
The second part to this method is getting the shoots to root. I have attached a work sheet that has been used in rooting explants in tissue culture and works with the shoots grown on the large stem segments; most plants will root in 14 to 28 days.
If you have a question please e-mail me.”
/s/ Earl Sommerville
Click >Novel Methods in Micropropagation The most pertinent part of this paper is the section entitled Forcing Large Stem Segments. Earl further told us:
“Retrieve the stems (up to 1 inch caliper) from a native azalea plant. They should be from 10 to 20 inches long, or up to 35 inches long if you have flats that long. Remove all the branches and leaves and lay the stems flat on top of a bed of perlite 2 inches deep. Watering is accomplished with a mist or drip system, or by hand. If you place the flat in a container to water from the bottom, never allow the water to go higher than half way up on the stem. It is important to never allow the perlite to dry out. Use a four-foot long two-tube light fixture 16 inches above the stems, to extend the day to 16 hours. Bottom heat is ok but not needed.
If the stems are collected in early spring (February-March) they will produce new shoots for three to six months. Stems collected in August will produce shoots for about four weeks.
Harvest the new shoots when they are about 3/4 to 1 inch long and place them in a plastic shoebox to root them, as explained in the note below.”
Establishment of Tissue Culture Plants (2.4 MB PDF file)
This handwritten note describes how to root the shoots you harvest from the long stems. Earl commented:
“The second part to this method is getting the shoots to root. The work sheet describes rooting explants from tissue culture; most plants will root in 14 to 28 days. Do not use bottom heat under the shoebox, for it is important to maintain an even temperature from 72 to 80; if you use bottom heat you will get gray mold.”
J. Jackson and Lindy Johnson, Trade TN have developed an approach to raising deciduous azaleas from seed to a full 3-gallon flowering shrub in three years, based on keeping the seedlings in active growth by repeatedly transplanting them to slightly larger containers when their roots reach the edges of their current containers. Here are the steps, in their words.
“We sow the seed on a common flat with a humidity dome in the late fall or early winter. Medium used is sphagnum peat moss that has been rubbed over a piece of hardware cloth to get the lumps out. These are placed under cool white fluorescent shop lights, 24/7 (we use 8′ units). Fish emulsion is used as fertilizer every 14 days after germination. They must be monitored and watered.
“About 90 days later the seedlings are transplanted from the common flat into a 50 cell 10″x20” tray. Fafard 3B is the medium we have been using for several years with some success. The plants should be trimmed at this stage to promote branching. Place back under the lights 24/7 until danger of frost has past. They must be monitored and watered. Fertilize every 10 days with Peters Rhodo/Azalea solution.
“In early- to mid-May (when danger of frost has past) we move the 50 cell flats to cold frames covered with 30% shade cloth. When the plants are “ready”(roots to the edge of the cell), about 90 days from transplanting into the 50 cell flats, it is time to move them into 4.5″ square cups (15/tray). We use Fafard aged pine bark for the media at this stage (we are experimenting with some Pro-Mix Bark mixture w/biofungicide 1n 2006.) They should be trimmed twice during the summer to promote branching. Fertilize with Osmocote Plus 5-6 month; 1/2 tsp/cup. The seedlings are grown in the 4.5” cups under 30% shade cloth until the next spring. Most seedlings are “ready” (roots to the edge of the cup) to transplant after they break dormancy and flush out in the spring.
“In mid-May of the following season we transplant from the 4.5″square cups into a 3-gallon squat pot filled with Fafard aged pine bark. 1-2 tbs of Osmocote Plus 5-6 month, is top dressed. The plants need to be trimmed at least once prior to 6/21 to promote branching and still have time to set bud. These are also grown in the cold frames under 30% shade cloth. Most of these plants are ready after 1 season in the 3-gallon pots.
“We over winter these plants in the cold frames covered with white poly; just place the trays on the ground and/or “jam the pots” close together in the cold frame. We usually place a layer of white pine needles on seedlings that are still in the 50 cell flats.”
The late Weldon E. Delp of Harrisville, Pennsylvania is famous for getting azaleas and rhododendrons to bloom very quickly from cuttings and seed. This is quite useful to a hybridizer, since the flowers are needed for evaluation and for any further hybridizing efforts. Click below to read the techniques he used, reprinted from the Journal ARS vol. 39, no. 1, Accelerated Propagation of Rhododendrons.
You can download PDF files of these two pages, including pictures, to read offline.
Accelerated Propagation of Rhododendrons – 1/2 (783 KB PDF file)
Accelerated Propagation of Rhododendrons – 2/2 (794 KB PDF file)