OUTDOOR PLANTING AND CARE
In all except mild or warmer climates, bare-root plants bought by mail from nurseries or garden-rose specialists should be planted in early spring, when vigorous root action and growth are beginning. Potted plants or any that come complete with a soil ball around the roots can be planted almost any time the garden soil is not frozen. But in sections where winters are severe, I think spring planting is always safest. In fact, in Connecticut I like to give new plants a longer growing season their first year by starting them a few weeks early, in pots, indoors or in the greenhouse.
Location
Plant miniature roses where they will get at least half a day of summer sun (a full day is best) but where it is possible to keep the soil suitably moist. Avoid low, muggy pockets where air does not circulate freely or where water can collect and make the soil muddy. Good drainage is vital. In cold areas, select a spot sheltered from icy winds by a wall or low shrubs.
Soil
To help keep them dwarf, miniature roses need a fairly heavy soil, but not, of course, too clay-like. Dig down at least ten inches, to prepare for the deep-growing roots, and improve the soil you remove with whatever is needed before you replace it around the plant. Clay-type soils will need the addition of sand, for drainage, and leaf mold needs rotted or dry cow manure or other humus to lighten the texture. Sandy soils need humus to help hold moisture. In even average fertile soil, miniatures appreciate an extra ration of humus at planting time.
The ideal soil for miniature roses will pack firmly around the roots, yet won’t cake and crack in the sun. It drains perfectly, so excess water does not stand around the roots, particularly in winter. Yet it holds enough moisture so that the roots don’t dry out so fast you can’t keep up with the watering job. Soil should also test neutral or slightly acid (pH 6.0), never extremely acid. In acid-soil areas, apply a light sprinkling of horticultural lime each winter.
Planting
Plant miniature roses about a half-inch deeper than they were before, and far enough apart so that they will have room to spread as wide as they will be tall. Crowded plants have no individual beauty, but they are prime targets for mildew. If the weather turns sharply cold or dry and windy after planting, protect the plants by mounding up soil around the stems. Remove it gradually as spring days grow balmier.
Watering
Miniature roses suffer seriously from drought, and will drop their buds and flowers after only a few days of hot, dry weather. Keep the soil constantly moist, and spray or mist the foliage once or twice a day. A mulch of pebbles, a mixture of half soil and half peat (peat alone packs down too heavily), or something similarly porous, will help keep the soil cool and moist.
Fertilizing
Light feedings of organic fertilizers such as bone meal or cow manure once a year, in early summer, are usually recommended. Or supply small amounts of a balanced garden fertilizer, or special rose food, in late spring and again in early July. A weak solution of liquid manure is also good and can be fed about twice as often.
Pruning and Training
In early spring, when new growth is first beginning to show on bush types, shorten all stems severely. I usually cut mine back to a uniform four inches. And of course, cut out cleanly any dead or mutilated branches. Make every cut just above a new shoot or leaf bud. Otherwise, pruning is limited to keeping the bushes shapely, removing faded flowers, and occasionally thinning the growth of old plants to admit air to the center.
Miniature climbers bloom on last year’s wood. They can be cut back to six inches when first planted, but are otherwise not pruned except to control ungainly canes or remove dead ones. Train the climbing canes into an attractive, open pattern as they grow, by tying them to the arch, fence, or other support they are to climb on.
Miniature tree roses can be cut back to a small but symmetrical head in spring and all dead wood should be removed. To keep them shapely, prune as needed during the growing season.
Insects and Disease
I protect my miniature roses, as I do the others, with an all-purpose rose spray or dust applied first when leaves begin to unfold, and repeated every week or ten days until the plants go dormant. Occasionally, during a long spell of hot, humid weather, I see signs that mildew threatens. If the all-purpose spray contains a fungicide (which most of them do), I use it immediately. If not, I may resort to dusting sulfur (which does mar the beauty of the flowers) or whatever sterilant is on hand.
Winter Protection
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.