INDOOR PLANTING AND CARE
Since miniature roses seldom spend the summer indoors, they are usually purchased in fall or winter from the local florist or greenhouse, or by mail from house-plant or miniature-rose specialists. Pot-grown plants are most likely to succeed indoors because their roots are not disturbed unduly. Except in Hawaii and Arizona, mail-order plants arrive with the soil ball complete about the roots, the stems cut back to about two inches. They start growth almost immediately, and flower within six to eight weeks.
If you have miniature roses in the garden, you can root cuttings in early fall and force them into winter bloom indoors. Or you can dig the plants, pot them, and give them their necessary dormant rest before you bring them indoors for forcing. Sink the pots to the rim in soil, in the cold frame or in some spot protected from severe winter weather. When the temperature dips low, mulch with salt hay, straw, evergreen branches, or the like. In late December or January, after six weeks or more of dormancy, lift the pots and bring the plants indoors. Prune back the leafless stems and water sparingly until new leaf buds appear.
After they have flowered indoors all winter and spring, I always plant my miniature roses out in the garden and let them resume their natural outdoor growth cycle. I may root cuttings, or I may bring others indoors the following fall; but I have never tried to force a plant a second time without letting it live at least one year in the garden first. I have heard that some growers (probably city dwellers or others who have no outdoor garden facilities) simply let the plants rest outside in summer—on a shaded ledge or in a window box with moist peat—prune them severely in fall, and grow them again. I haven’t heard how many years a plant will take this unnatural treatment or how much it suffers from missing its cool fall nap.
Soil
A fairly heavy potting soil packed quite firmly in the pot seems to help keep the plants small without sacrificing foliage or flower. One expert recommends a mixture of two parts garden soil, two parts humus, one part moderately coarse sand, with a light sprinkling of superphosphate or bone meal. When I use my ready-prepared potting soil, I always add sand, and sometimes some humusy soil dug from immediately under the leaf mold in the woods.
Potting
I’ve used both clay and plastic pots with equal success, always of the shape with the greatest depth, as miniature roses are naturally deep-rooted. Each pot has the usual layer of rocks or pebbles in the bottom for drainage. Small, newly purchased plants usually start off in three-inch pots, are shifted to four-inch pots before they become severely root-bound. Some larger varieties may take larger sizes.
Sun
This is one of the three important cultural requirements. Miniature roses must have sun if they are to bloom. A minimum of three hours is sometimes set, but I should think this amount would be applicable only to midsummer or to mild climates. In winter the plants need all the sunshine they can possibly get.
Temperature and Humidity
Second in importance is a cool 65 degrees or even much lower (maximum, 70 degrees), and third is the humidity which keeps the plants at their best. Leaves curl and dry, buds and flowers drop when the air is hot and dry. Miniature roses should not be set anywhere near a heater or radiator of any kind. Unless the air in the growing area is really cool and moist, set the pots on moist gravel or make some other provision for increasing humidity, as outlined on pages 76–77. It even helps to cover the plants with a tent of plastic every night, and let them emerge only for the day.
Watering
Keep the soil always moist, never soggy and muddy, never dry and caked. As a humidifier and refresher, mist the foliage as often as you can.
Fertilizing
A balanced soluble house-plant fertilizer (never one with high nitrogen content) can be fed in half-strength solution every three weeks beginning about three weeks after a freshly potted plant begins active growth. Or you can use any special rose food according to directions and at half the strength recommended on the package. The idea is to encourage the plant to grow and flower, but not stuff it with so much nutrition that it gallops gaily up to nondwarf size with leaves only.
Pruning and Grooming
I seldom prune miniature roses indoors except to cut off cleanly any stems that may have been accidentally broken or that may grow unattractively long or misshapen. I do try to douse the plants in slightly sudsy water, to clean the foliage, every few weeks; and I pick off faded flowers promptly. Actually, instead of being in continual bloom, these plants usually flower for a few weeks and then take a short rest before they send up buds again.
Insects and Disease
Again, preventive spraying is all I’ve ever done. I use my handy house-plant aerosol bomb almost every week. If disaster should strike, I’d probably use the special rose spray or dust I use on the regular garden roses.