Chapter 7

Propagation

Many plants can be raised from seed with a degree of certainty that they will be the same as the parents. This applies to types of simple breeding rather than to those of complex hybridization. Rose species can be reproduced from seed, especially when self-pollinated, but not so modern hybrids. New plants can be produced true to type from either species or hybrids by several methods known collectively as vegetative propagation budding, cutting, grafting and layering.

Layering

Layering is seldom done intentionally, but sometimes happens by accident. It is possible with climbers and a few dwarf varieties. It is most useful with those sorts that are not readily propagated from cuttings under amateur conditions, for example the Banksias. Most Wichuraianas layer very easily. Young wood gives best results.

By January or February the young canes will be long enough. The leaves should be clipped from the lower two feet or so of the selected cane, leaving only the heel, or petiole, of the leaf. The branch is then bent to the ground to ascertain both where to dig the hole and which part of the cane will become the actual bend in the layer. The hole should be about six inches deep to provide for a layer of good rich topsoil both under and over the cane.

The shoot must be "tongued" by splitting half-way through and in a slanting direction, with a sharp knife, on the underside of the cane and opposite an eye. Keep the slit open by inserting a small stone. The cane is then pegged in position so that, when covered, it will be two or three inches below the soil surface. It is best to use two pegs, one on each side of the tongue; this prevents sharp kinking. By June or July sufficient rooting system will have developed around the tongue to ensure safety in severing the cane from the parent plant and moving the layer as a new plant.

Left: MME JULES BOUCHE. Below: CHARLOTTE ARMSTRONG. Plate 18 Right: Rose cuttings prepared for planting. Left: Cuttings of R. indica major. i. With heel, incorrect when planting cuttings for stocks. 2. Unprepared cutting, thorns and eyes still present, no heel. 3. Correctly prepared cutting; all thorns removed; only uppermost eve remains. Plate 19

Grafting

Grafting of roses is almost unknown in Australia. In some countries where roses are forced under heating it is used to a certain extent. There are several methods.

Cuttings

Propagation by cuttings is unfortunately not as common today as in bygone years. There was a time when even keen home gardeners knew the names of very few roses. They frequently took cuttings, or slips, from others' gardens to their own. Often the newly acquired variety was named in honour of the friend from whose garden it came. These were mostly the old Tea roses.

The decline in the use of this mode of propagation is probably due to two factors: firstly, the huge expansion of commercial rose-plant growing, providing inexpensive plants in a well-advanced state; and, secondly, the difficulty in striking some modern roses as cuttings.

A rose plant grown from a cutting is often referred to as an "own-root" rose. It is a great pity that more of them are not being grown in suitable varieties. There are no suckers to worry about; the plants probably live longer; and there is no budding union where disease can occur and later destroy the plant. Roses that strike freely as cuttings and grow on to good big plants are all of sturdy types and seldom have much Pernetiana stock in their ancestry.

Wood suitable for cuttings is vigorous and healthy, amounting to a combination of bud selection and stock selection. Many growers report that the vigour and disease-resistance of own-root roses improve with each generation. This double selecting may be the explanation.

The best material for cuttings is from shoots that have bloomed. They should be cut with a heel of older wood. April, May, June, and July are the best planting months. The flowering shoot will have grown since February, the heel in the preceding few months. The entire cutting should be well-hardened wood, but less than nine months old. The upper part of the flower-stem, where the leaves are small, should be cut away just above the leaf, making a cutting six to nine inches long. Cut off all leaves.

Cuttings must be kept from drying before being planted. They can be stood in a container of water, covered with a wet bag, or buried in moist earth. Under Australian conditions they can be planted direct into the soil where they are to grow to mature garden plants, or placed in rows fairly close together for transplanting the following year. Rose cuttings are very sensitive to manure and strike best in unfed sandy soil. The lower end of each should be inserted four or five inches into the ground. In heavy soil some digging and soil-loosening are necessary. The cuttings can often be simply pushed into light soil. Press the earth firmly round them and water liberally.

The soil around all cuttings must be kept moist for at least six months. Feeding from their sap, nearly all will show leaf-growth in their first few weeks, but they will die later if allowed to become dry. A small percentage will die in any case. Always plant more than are required.

In recent years plant hormones have been used to increase and hasten root-formation on cuttings. The most common of these on the Australian market are Hortomone A, Seradix A, and Seradix B. They all contain indolylbutyric acid. The first two are solutions; the third is a powder available in three different concentrations, each coloured differently so as to avoid confusion. Seradix B Powder No. 2 is recommended for rose cuttings. The concentration of Seradix A or Hortomone A is varied by increasing or decreasing the number of drops used to each quart of water. No more than six drops of either to one quart of water should be used for Hybrid Tea roses, and up to twelve drops to the quart can be used for understocks. One quart of this very dilute solution will treat about three hundred cuttings. It should be made up fresh for each batch of cuttings.

Cuttings should be stood in the solution for eighteen to twenty-four hours, then thoroughly rinsed in water, and planted. When the powder is used the lower inch of each cutting should be dampened, shaken, and stirred in the powder. Tap it on the side of the carton to remove surplus powder and plant in the usual way.

To an amateur the saving of time in rooting is of little importance, for a mere few days is of no consequence by the time a plant is twelve months old. The increased percentage of rooting is useful to him. To a professional grower the main use of these hormones is in striking stocks, especially the more difficult types. Quicker rooting, larger root systems, and better striking percentage give him stocks of greater numbers and better quality.

Indolylbutyric acid is a synthetic chemical. The preparations ' are sold in small quantities, at low cost, and ample for all requirements. Naphthalene-acetic acid has also been used but appears to be inferior.

The rooting of any cuttings begins by the formation of callus, a cream ring of thickening, round the base. With the use of hormones this callus becomes as prominent in ten days as it does in four weeks under ordinary conditions. Many types of plants that could not formerly be struck from cuttings are quite easy to propagate with these preparations.

Natural hormones exist in all generating tissues, especially the cambium, from which callus and roots grow. Standing cuttings in tap-water for a few days before planting, or planting them in wet well-washed sand for a couple of weeks, will induce root-growth in some plants that will not strike in soil. Probably this improvement is due to the hormones being in weak solution from the cambium in the water or the sand moisture, and its being unaffected by soil contents.

Budding

In budding, a growth-bud or eye of one plant is inserted under the bark of another plant. The bud must unite with the actively growing tissues of the stock plant, as it is called. There must be an affinity between the type of plant from which the eye is taken and the plant into which it is incorporated. The two plants must be closely related but need not be of exactly the same kind. Most roses are easily budded on to other roses.

Often one finds an enthusiastic amateur gardener with a large rose plant, either dwarf or climber, with one or more other varieties budded on to it. Each budding becomes the focus of a plant of that variety. It amounts to several plants living on one root system. Flowering watershoots frequently come from the base of climbers. These provide a favourite site for this form of budding. Often the bud inserted is from a variety contrasting in colour with that of the established plant.

Budding is the propagation method of choice for nurserymen because it is economical and most universally successful. Collection of large supplies of cuttings of desired varieties of roses would be difficult, expensive, and time-absorbing. Each cutting has several eyes. Much wood, unsuitable for cuttings, bears many eyes. Some varieties will not strike at all, or strike in low percentage, or grow poorly from cuttings. These objections do not apply to budding. Usually, mature plants can be obtained from budding a year sooner than from cuttings, since most of them break into strong growth soon after budding.

The chief disadvantages of budding are the growth of suckers from a few plants in subsequent years and the requirement of more knowledge and accurate technique.

Roses and other plants suitable for budding have a layer of actively growing cells just under their bark. This is known as the cambium. It is about as thick as tissue-paper. When in a fit condition for budding it is smooth, almost shiny, and easily separated from the bark; then the cells are growing, and union with the bud is highly probable. In this union, the cells of the stock and the scion, as an inserted bud is called, remain distinct. Growth from each remains the same as before the budding, and in no way forms a hybrid. A line of demarcation always persists between stock and scion.

Stocks

A good stock has many prerequisites, the most important being:

1.	It must give a high percentage of striking as cuttings or of germination from seed.
2.	It must be easily budded.
3.	It must have affinity for a wide range of varieties.
4.	It must be capable of producing and supporting vigorous long-living plants as scions.
5.	It must be highly disease-resistant and not likely to in duce disease in the scion.
6.	Its budding incision and accidental wounds must be quick to heal.
7.	It must not readily sucker from the stems or roots.
8.	It must be available in adequate quantity.
9.	It must not need special or extra care and handling for striking.
10.	It must transplant readily.
11.	It must be readily adaptable to a wide range of soils and climatic conditions.

The ninth and eleventh of these qualifications concern the nurseryman more than the amateur who may not mind a little extra trouble with the few stocks he needs each year, and who will not worry if a stock that suits his conditions does not do well in another area.

A great number of varieties of stocks have been tried with varying results. Strangely, in Australia, different dwarf stocks have come to be used almost exclusively in various States. Queensland and New South Wales use R. multiflora; Victoria, Tasmania, and South Australia use R. indica major; Western Australia uses R fortunicma. Nearly all standard, or tree roses, are grown on R. canina, but in recent years a form of R. multiflora has come into use by several nurserymen, and at least one firm is using a stock known as IXL.

Cuttings for growth of stocks are slightly different from those chosen for propagating garden roses. No heel of older wood should be used. They should be as straight as possible, and all eyes except the upper one or two should be removed. This makes for greater quantity of available cuttings and less suckering, for each heel shelters many dormant buds that would later become a great source of trouble. Stocks should be planted in autumn.

R. multiflora is by far the world's most popular and widely used stock. It is grown in many varieties by different nurserymen, but in three main forms as seedlings for dwarf plants, as short cuttings for dwarf plants, and as long cuttings for standards. In all forms it produces a dense mass of fibrous roots, grows vigorously, is very readily propagated, makes a very close union with the scion, is highly resistant to sunburn and black spot, and suits a wide range of soils and climates. Its affinity for Pernetianas is strong, but not as good as some others for a few of the Teas and R. bracteata. It can be budded very late into autumn to give dormant buds for the following spring. It transplants well, and does not resent its roots being allowed to get fairly dry during the process. Cuttings seven or eight inches long and about as thick as a pencil can be planted direct into nursery rows with an expectancy of at least a ninety-nine per cent strike. Either thorny or thornless multiflora can be used for these dwarf stocks, but the thornless type is now the more common. One variety of thorny multiflora is claimed, by those who use it, to be highly resistant to cold conditions. It is often stated that roses on R. multiflora stocks do not live as long or grow as well in later years as those on R. indica major and R. fortuniana. I cannot agree with this.

Seeds of R. multiflora germinate readily in a seed bed in a few weeks. If the seedlings are graded for size at planting-out time, there is little variation in the plants at selling time.

When budded, seedlings are a little older than the cuttings. Insertion of the scion midway between the topmost rootlet and the lowest branch of a seedling ensures non-suckering. Seedlings are more costly than cuttings for the nurseryman.

Thornless R. multiflora is better than the thorny type for standards. Cuttings fifteen to thirty-six inches long and about half an inch thick are planted direct into the nursery rows. The soil is not hilled round them. All but the upper two eyes are carefully excised. These cuttings give about a ninety per cent strike and produce a plant with a big strong root system, green bark, and a very flexible stem. They always need staking in the garden, even as quarter standards.

Complaints about roses grown on R. multiflora stocks seem to be solely from people who allow their plants to become dry in hot weather. It seems possible that this variety of stock resents such conditions and so may not thrive in sandy soils. However, it does well round Sydney and Brisbane.

R. indica major is a form of R. chinensis and has become known in various parts of Australia as American Noisette, R. odorata, Boursault, Maiden's Blush, and Blushing Bride and, incorrectly, in Queensland as R. manettii. When mature cuttings half an inch in diameter are used, it has good disease-resistance, gives over ninety-five per cent strike, grows well, buds readily, and has an affinity for almost all varieties. It heals slowly after budding or wounding; this almost precludes late budding. It is rather susceptible to sunburn. It has a less vigorous root system than R. multiflora or R. fortuniuna. It is the cheapest stock to handle.

A form of R. ccmina is often referred to as the South Australian or Adelaide Briar. It must always be struck from two-year-old wood, has a poor root system, and is very apt to sucker. There are many better stocks for dwarf roses, but it is quite a good stock for standard or tree roses. The shorter standards hardly need staking. Many Pernetianas do much better on R. canina than on R. indica major. Canina standards do particularly well in light soils.

The great advantage of the IXL stock for standards is that it does not sucker.

R. fortuniana is stated as being a natural hybrid of R. laevi-gata and R. Banksia. It was tried as a stock in New South Wales in the latter part of the nineteenth century, but was discarded. Early in this century it came into use in Perth. It has an excellent rooting system and vigorous and continuous growth; it is easy to bud; and wounds and budding scars heal quickly. It appears to be specially suited to sandy soils. Its roots are credited with deep penetration, with consequent avoidance of the greater heat variation of the surface layers of soil. There are two great objections to it as a stock firstly, its poor percentage strike and, secondly, the marked resentment it has of its roots becoming dry at any stage of transplanting. All cuttings of R. fortuniana must first be inserted in sand beds until a good callus appears. They are then moved to the nursery rows, where apparently a seventy-five per cent strike is regarded as good. This all means much more labour, with consequent increase in the cost of production of plants. R. fortuniana has been used successfully as a stock for standards, but roses grown in this manner are not very popular in Perth, the centre of R. fortuniana advocates. Undoubtedly fine large dwarf plants grow in large numbers on R. fortuniana in very sandy soils around Perth.

Several hybrids of these stocks have been bred and tried, and some are promising. Only first-class stocks should be used, irrespective of their variety. Any that are not vigorous by budding time should be discarded.

Bud Selection

Having at hand understocks of good type and in condition fit for budding, buds or eyes of the rose varieties to be propagated must be obtained. There is a bud at the base of each leaf stem on young growth. On flower-stalks they are usually in best condition soon after the petals have fallen. The thorns will then snap off the branch when firmly pressed, leaving very little sap showing. Buds near the tip of a flower-stalk or climbing shoot are usually small and weak and may have already broken into growth. Those at the base are often immature. Only the plump well-developed buds between these extremes should be used. Immature buds are worth trying when there are insufficient good buds. If they take, they will need longer to shoot but will produce strong plants. Small weak buds are apt to give weak plants.

Tof. PATRICK ANDERSON. Bottom: ROD STILLMAN. Plate 20 Floribunda rose, RED PINOCCHIO. Plate 21

Buds should be sought only from strong plants and from strong branches that have given good blooms. The basis of good propagation is careful selection of both buds and stocks. Great diversity of growth habit is most often seen in novelties. The poorer plants are due to over-propagation. The demand is heavy and the supply limited. Then every available bud, good, bad, and indifferent, is frequently used. Often growth will be unusually good on just one part of one plant of a certain variety. This is actually a form of sport, but buds obtained from it will usually continue the improved type of growth in the whole of the new plant. This does not refer to watershoots in their first year of growth.

In the case of climbing sports of roses that were originally dwarf in habit, it is essential that buds be taken from young climbing canes. Buds selected from bloom stems will usually give a reversion to the dwarf habit. This is not so in varieties that are normally climbers and not mutants.

Prior to budding, the sap should be flowing freely in the stocks; this will be evident by the commencement of new growth. One or two heavy waterings may be necessary preliminaries. Sufficient growth should be cut away to permit working freely.

As the wood bearing the buds is collected, the thorns should be clipped to make for easier handling. This wood can be kept for many days standing in water, buried in damp sand, or under a wet bag. It can be posted to distant parts if wrapped in damp paper, then in dry paper, then in a double layer of grease-proof paper, and finally in a dry wrapping. Damp sphagnum moss can be inserted with advantage under the grease-proof paper but must never be allowed in contact with the budding-wood.

Bud-wood will keep for several months in a refrigerator provided the temperature is not quite down to freezing point and it is packed in an airtight container. This latter requirement is because the refrigerator dries the air to such an extent that the bud-wood shrivels. Maintenance of a steady moisture content is much more satisfactory than re-wetting the bud-wood from time to time.

To bud a dwarf stock, take a sharp knife, preferably a budding knife, and make a horizontal cut about one-quarter of an inch long just under the lowest branch. From the centre of this cut make a downward cut about one and a quarter inches long. These two cuts are in the form of the letter T, and only deep enough to slit the bark without damaging the surface of the wood the cambium. The two triangular flaps of bark at the sides of the vertical cut must be lifted gently. If the stock is in good condition this will be easy and the cambium will be slightly moist. Any difficulty will be due to the cut being insufficiently deep, or, more likely, to the stocks not being in good condition. In the latter case, thorough soaking will usually remedy the trouble within a week or ten days.

Before taking the buds, cut back the leaves so that about half an inch of each leaf-stem or petiole remains attached to the stem. This will serve as a handle by which to manipulate the bud.

The bud is removed from the budding-wood with a slicing cut from about half an inch above the eye to about the same distance below it. The piece removed is called the bud-shield, or bud-plate. It most commonly contains a thin shaving of wood in the concave side of the bark. Many propagators leave this in position, but the majority remove it if the bud is mature, and they seem to get the better results. The removal is done by inserting the thumbnail or fingernail between the wood and the bark at the upper end and peeling the wood from the bark. Separation should never be done from below upwards, for that would increase the probability of injury to the bud itself. Alternatively it can be done by very lightly pinching the bud-shield between the thumb and forefinger. If, after the removal of the greater part of the wood, a tiny remnant is left on or near the inside aspect of the bud, leave it there. If a depression is visible on the inside of the bark the growing point has been pulled out, the bud has been spoilt, and a new bud must be prepared. Buds must not be allowed to shrivel or be kept in water; they must be inserted as soon as possible.

Fig. 5. 1. Growth-bud of rose. 2. Bud-shield removed. A, side view; B, front view. 3. Bud-shield, side view. 4. Removal of shaving of wood. 5. Inner surface of bud-shield, ready for insertion, showing the eye intact. 6. R. multiflora seedling stock, showing budding incision below the "collar". 7. Standard stock, showing the usual dual budding. 8. Cutting stock. 9. Flaps of incision raised. 10. Bud-shield inserted. 11. Bud-shield tied in with raffia. 12. Raffia cut. A, too near the bud; B, correctly.

Grasp the prepared bud by the petiole and insert its lower end between the upper ends of the vertical cut. Force it gently down behind the triangular flaps until the lower tip of the bud reaches the bottom of the incision. This leaves the flaps gaping slightly and the petiole and bud protruding from between them. Cleanly cut off any bark of the bud-shield remaining above the horizontal cut. Then the whole of the bud is within the T-shaped incision.

The bud must be tied in tightly. Raffia, rubber bands, and many other materials have been used for this purpose, but raffia is usually preferred. Some propagators wet it before use, to make it more pliable, easier to tie, and less likely to loosen on tying. It soon dries on the plant, and in doing so, shrinks, making the tie tighter. Wrap the raffia round the budding, extending in close turns, from just below the vertical cut to just above the horizontal one. Never cover the bud. Tight tying keeps the under-surface of the bud in close contact with the cambium. A half-hitch at the top will hold the raffia tight.

Standards are budded by the same technique as dwarf stocks, but at a higher level. It is sometimes not possible to lift the bark of the main stem or trunk of the stock, especially when R. canina is used. Then a side shoot is chosen. The budding must be done on it within one or one and a half inches of the trunk. These stocks are the most costly of all, and so usually two or three buds are tied into different shoots lest one fails. In later years one will grow more strongly than the other. The weaker one is then removed. Sometimes buds of two different varieties are inserted, but they seldom grow equally well, the stronger type quickly outgrowing the other.

The buds take better if, for several days after insertion, they are not moistened by rain or overhead watering. The sap must be kept flowing; irrigation is usually necessary.

Each bud should remain green, and, after about three weeks, should begin to swell. To prevent strangling of the bud the raffia must be cut by a vertical slit down the side of the stock opposite the budding as soon as swelling of the bud is evident.

Withering of the bud indicates failure, and another bud should be inserted on the opposite side of the stock at a lower level.

TZIGANE. Probably the best bicoloured rose yet raised. Bred by Francis Meilland at Cap d'Antibes on the French Riviera, it is of medium size and good form. Plate 22 R. gigantea, the parent of all gigantea hybrids. Plate 23

Best budding results are obtained in warm weather, when the shade temperature is above 70 degrees Fahrenheit. The warmer the climate the longer is the budding season. In Queensland R. multiflora cuttings and seedlings can be budded all the year round. In Melbourne budding on R. indica major is restricted to January, February, and March. This is due to two factors climate and stock. In Perth the budding season is much the same. Autumn budding is a great advantage to both buyer and seller, for the rose sold twelve to sixteen months later has much more time to develop into a sturdy, attractive plant. This is not possible with imported novelties unless distribution is held back some months.

The swelling of the eye is the first stage of its shooting. Its union with the stock is very insecure, and remains so for several months. A thin stick should be driven into the ground beside each plant, and the first shoot of the scion lightly tied to it. This will prevent separation from the stock by wind, or by birds perching on it. Shortening of the shoot, too, will reduce risk of damage, and, in addition, will stimulate the growth of new and stronger base shoots from the bud. With novelties, this adds to the supply of budding-wood, but with climbing sports of dwarf varieties it may cause reversion to the dwarf habit; in their case it is best not to shorten growths.

With standards the lower part of a small stick may be securely tied to the upper part of the stock, and the shoot lightly tied to the upper part of the stick.

Particularly with R. multiflora stocks, allow big heads of growth to develop above the budding. It provides shade for the scion and keeps the sap running. When the eye has begun to grow, remove the entire top of the stock with all its branches by a slanting cut about an inch above the budding. This should be done before the bud has grown very much lest it be caught in the bushy growth of the stock and torn out.

Nearly all plants budded by February will be well advanced by June. A few will remain dormant, but an experienced grower will accept these willingly and look forward to more vigorous spring growth than from the more advanced plants.

All that now remains is to feed and water the young roses. Good stocks, good buds, and good technique will ensure good plants at low cost. You will learn much by doing your own budding, and, above all, value your roses as something you have helped to create.

An expert propagator will bud nearly a thousand roses a day, so you will realize that the process is neither difficult nor time-absorbing once you have had a little practice.

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