What you do to protect miniature roses in winter, or whether you do anything at all, depends not only on your climate but also on the health of the plants. If they’ve been growing well, they’ll take lots of abuse; if they’re weak and ailing, their chances of survival are reduced.
Sometimes, a flower pot inverted over the leafless stems is all that’s needed. Or you may mulch with salt hay or evergreen boughs. In Connecticut we mound up soil so it covers the first three or four inches of the stems, and remove it gradually in spring. It is most important to make sure that water does not stand around the roots in winter, next most important that alternate freezing and thawing don’t heave the roots out of the ground and break them.
If they are likely to be whipped by wind or covered with ice, the canes of climbing varieties are removed from their support and laid flat on the ground, where they can be covered with either soil or mulch. Since tree roses are inclined to be touchy, we wrap ours in burlap, with an extra layer or two around the graft and crown.
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.
NAMED VARIETIES OF MINIATURE ROSES
Although new varieties of this popular plant are constantly being introduced, and most likely will have a wide appeal eventually, it may be some time before they appear in plant and seed catalogues. In compiling this modest list I have thought chiefly of what is available at the moment, miniature roses I have either grown, seen in friends’ gardens, or admired vicariously on the printed pages of magazines, books, and booklets. If you are interested, I am sure these bushes are readily available. If I am old-hat and you feel avant-garde, there are many persons propagating new varieties. Talk to some of them, or try it yourself, a most gratifying hobby: