PROPAGATING MINIATURE ROSES
I’ve grown many miniature roses from seed, and had a lot of fun doing it. They usually germinate in about three weeks (best temperature about 60 degrees), quickly send out tiniest true rose leaves, and are ready for transplanting into small pots in another two or three weeks. I usually pinch the tip growth at least once, when the plant is about five inches tall. The flowers can appear within three months after sowing.
Of course, seedling plants are not named varieties. Most of them, in fact, have small single flowers in pale shades of pink or white. Your chances of double, more brightly colored flowers increase if you can get seeds of a good strain.
For new plants of named varieties, take cuttings in August or September—three-or four-inch pieces of healthy wood produced in the current season. If the stem can be pulled off gently with a sliver of the main stem still attached (a heel), rooting may be faster and is surer. Dipping the cut ends in hormone rooting powder is also helpful.
Make the moist propagating material firm around the base of the cutting, and make sure the air is kept humid in the propagating box or plastic tent, or invert a glass jar over the cutting. New growth is the signal that roots have formed and the cutting is ready for potting. These plants, too, will grow more compact and bushy if the tips are pinched out when the stems are about five inches tall.