(These few notes were compiled and condensed from the writings of Joseph F. Winchel by Bev Dobson to help beginning rose hybridizers get started. Our thanks to Joe Winchel for approving these notes and for granting permission to reprint.)
Hybridizing begins by artificially pollinating a variety with pollen from a different variety. Selecting these parents is very important. Start your pollinating program when the first blooms appear in the spring, and try to get all your pollinating done during the first cycle of bloom. The seed on some varieties will not mature in the northern states when the second blooming cycle is pollinated.
Be in the garden by seven o’clock in the morning if possible. Remove the petals from the buds that will open into full-blown blooms by noon of that day. By leaving five of the outer, or lower petals, it is easy to locate them when you return to place the pollen on them.
After removing the petals, remove the stamens (male part of the bloom that surrounds the pistil). Be careful not to injure the pistil (female part) in the center of the bloom, which is made up of more than a dozen stigmas.
The pollen sacs can be collected in a small jar lid and spread on a sheet of typing paper indoors away from the wind and sun for a day while the pollen sacs ripen and spill their pollen. The pollen can be separated from the sacs by screening. I used a fine tea strainer until I made a special screen by cutting a large hole in the tops of two baby food jar lids, placing a piece of fine screen between them and then soldering them together. The baby food jars are then screwed on, and the pollen screened by shaking just as you would a salt shaker.
The success of pollinating depends on placing the pollen on the stigmas at the proper time. This is determined by looking through a magnifying glass. On each stigma a sticky fluid exudes, usually in the afternoon after emasculation. Sometimes it happens the following day. When the sticky nectar appears on the stigmas, it is time to apply the pollen.
This pollen appears to the naked eye as a yellow powder, but it is actually tiny vegetative capsules filled with liquid male sperm. This sperm is released by the stimulating effect of the sticky fluid that exudes on the stigma, which dissolves the vegetative capsule, and the sperm spills onto the stigma, reacting to the chemical attracting stimuli of the egg cell, and later enters the egg cell where fertilization of the egg nucleus by the pollen nucleus takes place.
I prefer a quarter inch fine-haired artist’s brush for applying the pollen. It must be cleaned each time a different pollen is used. A pipe cleaner is also a good applicator, and can be discarded each time you change to pollen of a different rose variety. Place a label around the neck of the bloom with the name of the seed bearing (mother) parent first, then the pollen parent (father). Cover with a white paper bag to protect against water, sun and insects. Leave the cover on four days.
There are many ways to cross pollinate, and all will have a certain amount of success. The method described above is my most successful.
The greatest cause of seed hips falling from the bush prematurely is a heavy dose of fertilizer in late summer or early fall. The second greatest loss is squirrels and birds pulling them off. This is easy to correct by taking a 3-5 inch square piece of aluminum foil; place the center of it on the rounded end of a broom handle, and press the foil down over the handle. This will shape the foil to fit the rose hip. Removed the dome-shaped foil from the handle and set it on the rose hip. Squeeze the foil underneath to fit close to the neck of the hip so the wind will not blow it off. Leave it in place until you harvest the hips. The hips will actually mature and ripen better with the foil intact.
Some hips will ripen and drop a week or several weeks before the remaining hips are harvested. These are easy to spot laying on the found with the foil around them. Seeds from the hips that drop early usually germinate very well, it they were pollinated during the first bloom cycle.
In northern states hybridizers harvest the hips (with the label) late in October, or when the temperature drops to 30 degrees Fahrenheit. Where the growing season is longer and winter is less severe seeds can be harvested when the hips have been on the bush four months, or when they have acquired that orange-red coloring that tells you they are rips.
There are many ways to germinate the seed. One that has worked well for me is to leave the harvested hips in a plastic bucket covered with Saran wrap in the garage where the sun cannot shine on them and where the temperature is between 40-60 degrees Fahrenheit. In a month I shell them and submerge the seed in a mixture of 1/2 teaspoon of 50% Captan in 1/2 pint of water to prevent mold.
Use a tray 2-3 inches deep with plenty of drain-holes drilled in the bottom. Fill with a 5050 mixture of medium vermiculite and Canadian Sphagnum Peat to within 1 inch of the top. Add water until the mixture is saturated. Lay the seed on top in rows. Be sure the labels are in place. Cover with at least 3/4 inch of silicon sand and moisten with Captan in the water to prevent damp-off.
The seeds will start germinating in about six weeks, if they are kept moist and the temperature is maintained between 55 to 60 degrees Fahrenheit, and may continue for about two months.
The sterilized potting soil for the seedlings to grow in should be coarse and porous for good air circulation. With each bushel of soil add two cups of organic rose food and one cup of 50% Captan. The growth obtained from this mixture has been terrific for me, and the plant loss from damp-off has been zero, but I keep the temperature in the growing area from 65 to 72 degrees Fahrenheit.
Growing seedlings under fluorescent light fixtures with 40 watt, four foot long Gro-Lux tubes is very practical.
When the rose seedling is two days old, it can be transplanted from the sprouting medium to the potting soil where it will grow. Place the container with the newly planted seedlings under the Gro-Lux tubes with four inches of clearance. Have the lights on 16 hours and off 8 hours each day.
The seedlings that sprout in January will be blooming in February and March. If the first bloom is of poor quality, pull the seedling out. This will give those near it more room to grow. It will also lighten your work load. Poor blooms will have to go sooner or later - the sooner the better. After observing the blooms of several thousand seedlings, I have reached the conclusion that as many seedlings are rejected because of narrow petals as all other reasons combined.
Observe and evaluate your blooming seedlings every day all during the first blooming season. Pull out all that do not meet your approval. Those with vegetative centers, not enough petals, poor form, poor color, poor substance, poor plant habit, poor foliage, and those that are overly susceptible to fungus disease must be discarded.
If you get a seedling that has a bloom with unusual, unique, novel color, entirely different than anything you have ever seen, keep it for breeding stock. Even if it has only five petals or if it has sixty-five. Even if everything is poor, but the color is unusually beautiful. By crossing it will other good roses, you probably will be able to get a good bloom with that good novel color on a good plant. In a period of five years you can do wonders with a novel color.
Those that are good enough to keep beyond the first year should be budded the first summer. The bud take is better in the summer than in the fall. If you live east of the Rockies and north of Texas, the best root stock is R. multiflora year-old seedlings. If you live east of the Rockies in a southern state from Texas to the east coast, thornless R. multiflora cuttings are your best root stock. Dr. Huey is the favorite on the west coast. R. canina is used in Canada and Europe because it is winter hardy in those climates.
Good Luck and Happy Hybridizing!