Early summer is a good time to take cuttings and root new growth of roses, azaleas and several other kinds of plants. By following a well-tested method, even the inexperienced can expect to get good results.
Humidity is important. When the air is moist, relative humidity is high and transpiration [loss of moisture through the leaves] is low. Thus, if high humidity can be maintained around the cutting, the problem of wilting is taken care of. That is why a greenhouse is valuable for rooting cuttings -- high humidity is easy to provide.
With the advent of polyethylene plastic, it became possible to provide high humidity at little cost or trouble. Carbon dioxide and oxygen can pass through the plastic but water vapor cannot.
Early morning is the best time to take the cuttings. They should be four to six inches in length, depending on the plant [four inches for azaleas, six for roses and forsythia].
Use a sharp knife or razor blade to take the cuttings. The stem should be cut cleanly and not crushed. Make the cut about a quarter of an inch below a node [the junction of a leaf and stem]. Remove all but the top two leaves.
Put the cuttings immediately between moist newspapers or cloth. If they dry out, they will wilt and if they wilt they will not root.
Cutting should be planted immediately, but they can be stored for a few days in a slightly moist plastic bay in the refrigerator or some other cool place. This method can be used to bring cuttings home from a distance.
A 6-inch clay pot can be used but a larger or smaller size is satisfactory. Wash the pot in boiling water before using it, to be on the safe side.
For azaleas and other acid-loving plants, the mixture should be peat and vermiculite or perlite in equal parts. These materials are available at most large garden centers. For roses, forsythia and similar plants, use two parts vermiculite or perlite and one part peat.
The medium should be moistened before putting in the cuttings. Cuttings should be inserted to about one third of their length, at a slight angle, and just far enough apart not to touch each other.
After planting the cuttings, water the medium again and then enclose the pot in the plastic bag.
A hormone, such as rootone or hormodin, can be used to speed rooting; it isn't essential but it does speed things up.
For the first week or two the cutting should be kept in light shade. After roots start to form, the shade can be gradually reduced. After cuttings are rooted, the plastic covering can be removed for short periods allowing the plants to adjust gradually to the outside world.
Shade them for a week or two after transplanting to individual pots to help them become established. Then gradually increase the amount of light.