Growing Roses For Cut Flowers

Roses are deciduous shrubs and climbers of great diversity in habit, foliage, fruit and flower.

These differences arise from their far flung natural distribution, all around the temperate zones of the northern hemisphere.

Popular practice puts the Queen of flowers in a bed. Whether so used, or as a flowering shrub, hedging plant, climber or standard, she is valued by many as the most desirable of garden plants.

Roses are normally grown in the open, being so hardy as to render winter protection uncustomary in Britain, but they also grow well in greenhouses, and in pots.

Their great advantages are beauty, ease of cultivation, cheapness and long life.

Growing Conditions

Roses require a soil which retains moisture but permits drainage. The more fertile the soil the better because roses grow readily in response to fertility. Tolerant of alkalinity or acidity, they are unhappy only at the further ends of the scale, more particularly at the acid extreme. They are not shade plants; they prefer to grow in the sun. Roses usually endure exposed places well, with some inhibition of growth.

planting roses

Soil Preparation

The three objects are to feed the plants, to give them anchorage and to drain the soil. Deep digging attains all three, preferably by trenching, at the same time thoroughly mixing organic substances with the soil. But preparation must be adapted to the soil, of which here follow four instances.

A soil impervious to water (which may be tested by filling a hole with water to see if it drains in forty-eight hours) demands the lower spits be broken, and if necessary a soakaway provided, to prevent the bed becoming a sump for the surrounding area. Render heavy clay more porous with gypsum (calcium sulphate) at about 3 lb. To the sq. yd. In the bottom of the trench.

A soil with a high water table will only grow roses if the beds are raised.

A shallow soil which drains well needs to be dug only for the purpose of adding food, particularly substances to hold moisture. The lower spit may be replaced with better soil. Beds must not be raised on such soil because in the summer they dry out.

A fertile, well-drained soil need only be cleaned, levelled and planted.

Planting

Buy good strong plants, and be suspicious of cheap offers. Plant October to April when the soil is crumbly. The ground is the place for roses, but if they cannot enter it at once, keep them in a cool place, not in a heated room, for the briefest possible time. If the soil is not crumbly, plant them temporarily elsewhere, close together and firmly, with the roots wet. Do not plant in prepared ground until it has re-settled.

The average planting distances to create a close array are: miniatures 12 in. ; dwarf floribundas 15 in. ; floribundas and hybrid teas 21 in. ; shrub roses 42 in. ; climbers at least 10 ft. apart, and standards 4 ft. But all may be grown individually at optional distances, and standards in particular do not really need to be closely set.

Use a good seed and potting medium as a planting mixture; or enthusiasts can make their own by mixing two handfuls of sterilized bonemeal (use gloves) and one of hoof and horn to a large bucketful of peat. Do not let other fertilizers or manure touch the roots.

Trim off snags, suckers and damaged or immature growth before planting, and wet the roots. Dig a shallow hole, and place the plant to one side of it, with the roots spread out on the bottom, towards the horizontal. Place at soil level the point where thorny stems and smooth rootstock join. If the plant does not sit comfortably, deepen the hole —6 or 7 in. is usually deep enough. Cover the roots first with planting mixture, then half fill the hole with soil, and tread very firmly for rose roots must be tight to the ground. Fill the hole, tread lightly and level off. The plant should resist a firm tug. When filling up, take the soil from the next planting position, and the next hole is ready dug.

Put the stake in before the standard, the top of it just below the lowest graft.

When the soil is dry in April to June tread again, especially any slow starters, which will also benefit from a bucketful of water.

Roses grown in containers must be planted (after removing the container) with the soil closely firmed to the sides and bottom of the container soil, which should be moist. Planting time, obviously, is optional for container plants.

Pruning

A rose shoot normally grows to its terminal point in one season. It exists in the future by means of side shoots, which are usually incapable of girth greater than the parent shoot. By pruning, only the strongest wood is left, and new growth is therefore obliged to arise from it.

Such, in a nutshell, are the reasons and methods, to which we add one fact : after a few years, rose stems resist sap flow, which is forced into new growth elsewhere on the plant, whereupon the old growth system can be cut away.

Efficient secateurs and a narrow-bladed saw are the tools. The time is winter or spring, before growth is far advanced, but it is well to shorten the plants in November or December to reduce wind damage. Cuts are made just above an eye, without injuring it, and on a slant of which the eye side is the higher. Unless the plant’s development demands otherwise, an outward-facing eye is chosen. All weak, unripe, damaged or dead wood is removed.

Prune new plants hard : bedding roses being left about finger length out of the ground ; flowering shrubs up to 1 ft.; climbers 2 to 3 ft., and standards about 6 in. from the grafts. When the plants are mature, strong growths can be retained to any length; they will develop into a considerable system, which may be encouraged and retained, with suitable shorten ing of the side shoots, or of the whole system if the top of it is becoming unproductive.

Exceptions are many belonging to the group known as the old garden roses, which grow one year, and flower the next. Unless adequate length is retained, the flowers will have been pruned away. Wild roses look more graceful if the long shoots are not shortened. Standard roses do not replace growth as easily as the others, and caution is needed in removing large parts of them.

The long growths of climbers are trained to fit their position, and in future years their side shoots shortened: or the best may be trained. The main stem is kept until it is not satisfactorily productive, when it may be removed entirely, or shortened to a point where it is productive.

Cultivation

After pruning, shallow cultivation by spade or fork will tidy the beds; but only an inch or two deep — the roots hate being disturbed. Weeds may be controlled by the hoe, or by weedkillers or suppressants, first ensuring the herbicide may safely be used among roses.

Fertility is increased by the proper use of mulches, soil fertilizers or foliar feeding: it is better not to use fertilizers in the first year after planting.

The best mulch is good farmyard manure, applied to the surface in May. Alternatives are compost, leafmould or peat.

Fertilizers for roses are so carefully prepared by the leading manufacturers that most people can safely buy them, and apply once after pruning. It goes down more quickly if spread on a frosty morning. A second dressing can be applied in June when the buds have formed, preferably in a rainy spell. Ideally, fertilizers should answer the needs of the soil, which can only be discovered by expert analysis, and in cases of difficulty this is a sensible procedure.

Never use any fertilizer containing muriate of potash; Nitro-chalk is unsuitable for chalky soils; sulphate of magnesium should be a constituent of a good rose fertilizer, for magnesium in a small amount is an essential rose food. Lime must be used with caution, only on a soil proved to be too acid without it, and preferably in the form of calcium carbonate.

Foliar feeding is especially useful if the soil is alkaline or chalky.

Suckers should be pulled or cut off, as soon as noticed. They are recognized by their different leaves and by their point of origin being separate from the grafting union. It is not true that they can be detected by counting their leaflets.

Fading flowers should be dead-headed before they set seed to induce new flowering shoots; ideally, trim them down to the next sound eye, but failing that, trim them off quickly.

Pests and Diseases

Be prepared with efficient sprayers and remedies because troubles spread very swiftly. The chief enemies are greenfly, mildew, blackspot and rust. The leading companies have good remedies for each, and regularly introduce new products.

Greenfly killers should be applied when the greenfly become obvious.

Mildew is a light greyish mould; look just under the flower buds for early warning, and spray when seen. Current remedies include those based on dinocap, dodemorph, benomyl and chloraniformethan.

Blackspot and rust are the most damaging diseases. Blackspot shows as irregular black spots on the leaf, and rust as orange (later, black) pustules underneath it. Current remedies are maneb for both, captan for blackspot and thiram for rust. These two diseases need preventive spraying, from pruning time until flower buds form, if there has been any sign of them in the previous year; and remedial spraying after flowering should the diseases appear. Prevention is more effective than cure, and the undersides of the leaves must be sprayed as well as the tops.

The choice of varieties resistant to fungal diseases is also a sensible precaution.

Lesser pests are thunderflies (thrips) and leafhoppers, which are controlled by greenfly killer; caterpillars and sawflies, which make the leaves curl up, for which trichlorphon is effective, and red spider mites, like miniature spiders, slightly mobile, on the undersides, for which white oil may be used, although new products are now being tested.

Classification of Roses

In 1971, The Royal National Rose Society produced a framework of classification, which we simplify here as follows:

MODERN GARDEN ROSES

  • Large-flowered bush roses (Hybrid Tea) Cluster-flowered bush roses (Floribunda) Shrub roses Miniature roses
  • Climbing roses

OLD GARDEN ROSES

  • Shrubs and climbers

WILD ROSES

  • Shrubs and climbers, either wild, or hybrids resembling wild roses.

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