Proceedings Library

An attempt to form a chapter in Britain was made 1960–61 but proved abortive in spite of some hard work by a number of enthusiasts over here. In order to profit by any mistakes which might have been made in the past the reports and correspondence of the earlier effort were re-examined carefully. It was clear that the effort failed because the nursery industry as whole was just not ready for the concept of all that I.P.P.S. stood for. Free interchange of knowledge and experience was not yet generally acceptable and the "locked door" still epitomised the propagation

My publisher, being an amateur gardener himself, has pressed for the inclusion of lists of species and varieties, with best dates, percentages rooting, etc., but I have resisted this. There is much published data of this kind which I could have drawn on but, in general, it is so conflicting and inconsistent that no really useful purpose would be served, other than broad conclusions that certain varieties are "easy", certain "medium" and certain "difficult to impossible".

To be scientific an experiment needs to be carried out under conditions so well known that it can be repeated elsewhere, later, by another operator with identical results. But where, in all the welter of recorded results of mist propagation experiments, can there be found data which any of us

The task of the chrysanthemum cutting propagator is to produce the correct quantities of the required varieties each week of the year as dictated by these growers programmes.

This entails putting into the rooting bench in excess of 1 million cuttings each week and removing a similar quantity for despatch to the customers, and our problems are therefore to a large extent organizational.

Cuttings are produced on stock nurseries in the South of England and to obtain the benefit of winter light we produce a large percentage of our sale cuttings in the Canary Islands.

The stock nurseries take cuttings from stock plants by snapping them off at a previously determined length according to the use to which they will

My first experience of grafting this subject dates back to the early days of the Second World War, when for obvious reasons our supply of this tree abruptly dried up, so if we wanted to maintain a stock we had to go it alone. With this end in view, my boss suggested that I tried my hand at grafting them for ourselves, and in the autumn of 1940 I hurriedly potted up fifty stocks of Picea excelsea.

We had a well established tree of Picea ‘Kosteriana’ in the nursery, and in the following January I was able to collect fifty suitable scions. Without delay I grafted these on the Picea excelsea stocks using the simple side graft and placed them on their

One's first impression is of complexity. There are well over fifty officially organised authorities doing at least some propagation research, or fundamental scientific work of direct benefit to plant propagation. To simplify I will place these under seven headings.

1. Research Stations.
2. Universities.
3. Botanic Gardens.
4. Forestry Institutes.
5. Experimental Horticultural Stations.
6. Horticultural Colleges.
7. Commercial and private establishments.

The amount and character of propagation work at these places varies tremendously. Five research stations, Long Ashton, East Malling, John Innes Institute. Glasshouse Crops Research Institute and the Scottish Horticultural Research Institute have extensive programmes. For example, the G.C.R.I. is

Having used this system with considerable success since 1965 we feel that it is most important to enquire first how much further we can go in cold storage techniques. Answers to the following questions would considerably extend the economic utilisation of the cold stores.

1. Hardwood seed has been stored in Europe for twelve months; conifers much longer, up to about 4 years. Is it possible to extend this without losing viability?
2. What method of storage is most suitable? We have found that mould has developed in containers but surprisingly not in sacks.
3. What is the optimum temperature for various species — conifers and hardwoods? We have used 32°F here down to 28°F. On the Continent, I believe, temperatures down to —5°C are used.
4. Humidity is an important factor; 94–96% is normal at Tilhill. Is there any difference in

I think most of the propagation techniques have been, and are still being developed by trial and error on the nursery and sometimes under very poor conditions. It would be a great help, therefore, if a scientific mind, together with laboratory conditions, could assist us with some of the problems of modern and economic plant production. Into this field must come hormones. It is almost impossible to compete in commercial plant production without them. The time to produce a root is sometimes shortened by weeks and the root system produced is far superior as a transplant to cuttings rooted and untreated. I think a larger range of hormones should be available to the propagator than at present exists, in both

1. The Bloxer*
2. Various rooting media.
3. Capillary beds.

We now have nearly two acres of capillary beds in and out of doors using the N.I.A.E. method, this way we have a tank and ball valve maintaining water level in channels spaced five feet apart, 3 inches below the surface of the sand.

We have had three main problems to solve:—

1. Removal of rain water. This, we have overcome by laying a land drain beside each bed.
2. Wind blowing plants over. This, we have only partially solved by caning and then supporting the tops of canes in strips of netlon held between two wires. For lower plants we sometimes use wind-breaks of some sort. This, must be a bigger problem when a

A compost is an attempt to simulate an ideal rooting medium for a particular plant.

One of the first recorded studies of plant growth and nutrition was by Woodward in 1699 when; on growing vetch, potatoes and mint in water obtained from various sources, he concluded that water was merely a carrier of terrestrial matter.

Our aim as nurserymen is to produce compost suiting the particular plant in question so as to provide the correct amount of water, nutrients and aeration. As a result of this coupled with a favourable climate and light intensity we should achieve maximum plant growth.

The practical qualities of this ideal compost should be:—

1. cheap to produce,
2. standardised quality,
3. good reserve of nutrients,
4. wide spectrum of usage.

How can we achieve these qualities

In our container department we use only two different mixes of compost, a general purpose compost for the vast range of trees, shrubs and conifers and a special acid compost for ericaceous and allied

Boskoop is the most important nursery centre in Holland. It covers a total area of around 1500 acres which is made up of approximately 750 nurseries. The average size for a nursery is about two acres and because of this small size, production is very intensive. The top soil is ideal for nursery stock production and is composed of 34% peat, 28% clay and 38% sand. The soil pH is in the region of 4.5 — 5.5. Despite many advantages the nurserymen face three major problems. These are as follows:

1. The peaty-

I have been asked to say a few words about the project here; The Gardening Centre is a permanent exhibition for the gardening and horticultural trade. The project is actually run as a company, The Gardening Centre Limited, which was formed in 1965 between the two share-holders — Imperial Chemical Industries Limited through its subsidiary Plant Protection Limited, and the Duke of Northumberland. The two share-holders are in the proportion of 75% Plant Protection, and 25% to the Duke — which amounts to a share capital of 100,000.

During the first phase of the project to opening day, on May 1st 1968, approximately £500,000 have been expended here at Syon. The initial preparations of the grounds entailed major engineering works. A few details of these are that about 4½ miles of paths had to be laid

M. G. ADCOCK: Take them at the end of September on last year's growth with just one node with the leaf bud inside. Bottom heat of 65–70°F is desirable. A compost of 3 sand and 1 peat is best and a rooting hormone should be used after slightly wounding at the bottom. The cutting is reduced to 3 or 4 leaflets and the crown bud can be used if required. We root in boxes and pot on later.

CHAIRMAN: Comparing most cuttings under mist with those in a closed case the mist cuttings row away in the same spring whilst those in the case generally don't grow away until six months later. Mahonia ‘Charity’ and M. japonica root readily.

A MEMBER: But not Mahonia rotundifolia.

PETE DUMMER: The problem is the ripening of the wood. Cuttings of the last named should be taken earlier, in August, when the wood of these is ripe.

CHAIRMAN: The cuttings should be called "leaf mallet" cuttings

The production process or system currently used for started eye and two-year rose plants may be subdivided into approximately 12 major stages or steps. (For dormant eye plants, a step (9 below) is omitted.) These are:

1. Preparation of the land.
2. Gathering, processing and lining out understock cuttings.
3. Gathering, processing and storing scion wood.
4. Providing cultural care for the growth of the understock prior to budding of scion variety.
5. Budding.
6. Cultural practices to assure union of bud.
7. Removal

In looking back, it seems to me that among the more significant of my early discoveries was one that made itself apparent after a series of frustrating experiences associated with failure.

My first experiences in the making of exploratory rose crosses, while not entirely failures, were sufficiently so as to make it appear expedient to evaluate the factors involved in the failures and further, to try to give them a rating as to importance.

In casting about for some apt title for this procedure (entirely for my own use I have thought in terms of a phrase which is meaningful to me, "A Priority of Limiting Factors."

I shall try to illustrate what I mean by using some actual experiences and telling of them in the

At present, by far the most popular

The techniques of rose propagation are basically simple, highly standardized, and for the most part are quite successfully accomplished by most of the rose growing firms. However, in California today it appears that the greatest emphasis, and the major problem solving requirements, center not so much on the art of propagation, as such, but rather in the field of production.

The basic difference between propagation and production is chiefly one of dimension. The production function, as I will define it for today's discussion, is the art of propagation performed on a large or massive scale. Production of field grown roses goes far beyond the individual propagator. Field production is chiefly the responsibility of a highly qualified professional production staff

The importance of keeping plants healthy has long been recognized. One of the first papers on this subject was published in 1723. Since that time, much progress has been made in this field, but there continues to be room for improvement. The key to any program depends upon knowing the life cycle of the pathogens that you are trying to control and then developing the necessary sanitary facilities to keep these pathogens from the plant's environment. This goes back to the old phrase often used by Dr. Baker, which is; "don't fight 'em. eliminate 'em".

One of the best reviews on sanitation in

The need for virus-clean stock.—When damage caused by viruses is not conspicuous, losses are often difficult to ascertain. A moderate reduction in fruit set, fruit size, or tree or vine size may easily go unnoticed or be attributed to cultural or environmental factors, especially if all plants in a

Regulatory and industry activities in past years have been directed toward reducing pest infestation through visual observation of plants and by quarantine restrictions. Experience has shown that certain plant pests can be present that were either not recognizable

Before getting too deeply involved in my subject, could I clarify that both potting and containerizing refers to the same process, the former being used more widely in this country, while the word ‘containerizing’ has been introduced from

In the early stages of developing the Certification and Registration Program, Department of Agriculture members visually inspected bud sources in selected grower orchards. Visual inspections culled out the bud-source trees most severely infected with ringspot or other viruses.

At the time, bud lots were mingled on a variety basis, and no effort was made to ascertain the

The California Citrus Certification Program was initiated more than 10 years ago and not a single certified citrus tree has been dug and sold by a commercial nurseryman to date. No apologies need be given for this fact in my opinion; perhaps compliments are in order. The California Citrus Nurserymen are operating under an interim Registration Program. I believe that the citrus industry would assess this program affirmatively.

Within the next two years however, commercial digging of certified trees will commence. When sufficient volume is available, the citrus nursery industry will be required to evaluate the interim Registration Program and decide whether to terminate or continue the program.

At this point potential danger does exist in cutting excessive buds from a relatively

We have become increasingly conscious in the last few years of a phrase which we now know is being uttered too often. The phrase goes something like this: "I don't like roses because they are too much trouble." When we get this clarified, we find that "trouble" means spraying for various types of pests, in about 90% or more cases. It seems dubious that the plant breeder can do much about breeding roses resistant to insect pests, but it certainly is feasible for us to consider and hope for results in breeding for disease resistance.

We have become

Research in plant propagation in the past 35–40 years has been dominated by uses of auxins (11) and mist (13). L. H. Bailey, in the 1920 edition of his classic Nursery Manual, gave scant attention to the role of the rooting medium in the process of root initiation. Little attention has been given to the chemical nature of the rooting medium. An early study by Hitchcock et. al. (4,5) found that rooting was affected by pH of the medium. Laurie and Chadwick (6) reported differences in rooting between peat, peat-sand and sand media. Media influenced percentage rooting, number and length of roots and in certain species, position of roots on the stem. Although the media differed in a number of properties, quantitative measurements were not given. More recently Raabe and Vlamis (10) showed the effects of sodium-calcium ratios of peats on rooting of chrysanthemum. Paul and Smith (9) studied rooting of chrysanthemum in peats of varying exchangeable calcium-hydrogen content. The

The major cations contained in natural waters are sodium (Na), calcium (Ca) and magnesium (Mg). Major anions are chloride (Cl), sulfate (So₄) and bicarbonate (HCO₃). The cation of chief concern is sodium. Waters with a high sodium hazard rating are unsuitable for irrigating purposes since they can cause alkali

Presently, most Colorado spruce plants are raised from seed. If the seed is collected from blue parents, the offspring may vary from 10% to 60% with 20% blues considered a very good result.

Grafting is frequently used for strains of Colorado blue spruce such as Koster blue spruce. Grafting has advantages of generally quicker results and uniform plants. Many people feel that a seedling understock will give a better plant. The disadvantages are that it takes experienced help to do this grafting and this experience help is usually hard to get. Conditions where these grafted plants are kept are also quite critical.

The next way of reproducing plants is by cuttings. In talking to most nurserymen, Colorado spruce are very difficult to root from cuttings, and when they do root, roots are typically poor and claims are that

In discussing such a wide embracing topic as the sexual propagation of woody plants, I have decided to make some general observations, and explain some of the techniques that are employed at Plumfield Nurseries, Fremont, Nebraska. In glancing over our shoulder through the Proceedings of past meetings of the Society, there have been many words pertinent to seedling propagation. One of the very finest reviews of this topic was a paper presented at last year's Eastern Region meeting by Dr. Steve O'Rourke. I quote from his

We greet all customers on arrival and encourage them to browse. For stock we carry a wide variety of plants including:
          Bedding plants
          Herbs and vegetable plants
          Ground cover plants
          Water plants
          Cactus
          Hanging baskets
          Espalier plants
          Standards
          Summer flowering tropicals
          Small trees
          Large balled trees to $500 size
          Azaleas and rhododendrons
          Ferns, outdoor and indoor
          Roses
          Fruit trees
          House plants
          Large indoor plants to 16' high for offices and banks
          Bromeliads
          Citrus
          Pot mums and other seasonal potted plants
          Orchids
          Tubbed and potted plant specimens for house and patio

All plants are kept in a healthy condition by using constant feed, spraying

A number of field studies have been conducted looking at two aspects of the use of selective herbicides for weed control in container-grown plants. The first question is tolerance of woody ornamentals to herbicides, the second is weed control. Several extension workers and nurseries have cooperated in these tests. Extension workers involved include Jim Breece, Clyde

Before going into the actual part of herbaceous propagation itself I should like to explain the position we at Bressingham are trying to fill in the horticultural industry and the trends we see from our vantage point in Norfolk.

Most nurserymen would agree I think that the general trend has been towards roses, trees and shrubs over the past few years. In consequence most general nurseries have tended to concentrate on these lines and as herbaceous plants were always the last to be planted, and usually were the most uneconomic, due to high labour costs and a low profit margin, then it often followed that herbaceous were the first to be dropped. If not dropped altogether then they were bought

The first group of systemic fungicides to be developed belong to a group of chemicals known as oxathiins. These were first obtained

The work reviewed below is not necessarily "new", but, since there appears to be a 10–20 year lag between discovery and true application of growth regulators, it may be important to review the synthetic compounds made available over the past two decades. Present studies with naturally occurring compounds are more likely to sound "new" since they are still in the laboratory stage. However, they suggest outstanding opportunities for the development of additional chemicals of economic importance and will be discussed first.

1. Naturally Occurring Compounds


1. Abscisic acid (and related substances)

There is little question that the isolation of abscisic acid (ABA, abscisin II, dormin) from many different plants is having the same impact on our

Disease control measures may be divided into two major groups: 1) prophylaxis and 2) immunization. Prophylaxis implies the protection of the host from exposure to the pathogen, from infection or from the environmental factors favorable to disease development. Immunization refers to improvement of resistance of the host to infection and to disease development.

In the propagation of plant material from cuttings or tissue cultures, prophylaxis is the major approach to disease control since comparatively little is known about disease resistance in ornamentals. Disease control in this area, therefore, can be

We want first to define what we mean when we talk about plant tissue

Are such compounds for disease control available? Certainly the entomologists can control insects with systemic insecticides like phorate and dimethoate. The physiologists can supply us with a host of systemic herbicides. Where do we, as plant pathologists, fit in this development of systemic compounds to control the pathogens?

I must admit we are far in arrears of the entomologist and physiologist but developments are rapidly emerging. The egg has hatched!

Prior to 1966 our only meager achievement was in antibiotics such as actidione and blasticidin S. The former controls several diseases such as hawthorne leaf spot caused by a fungus. A single application of 1 part per million in late June will control this disease, even though

When a new collector gets the plant fever, the first plant he usually buys is a weeping hemlock. The Weeping Canadian Hemlock reproduces fairly true from seed and in some cases, even better. Viable seeds are hard to come by. The germination is very poor and erratic. This plant can also be propagated from cutting by using Hormodin #3 on the current year's growth and

The customer, the consumer of our products, will define a dwarf conifer as any plant that will remain small. How small he doesn't know, except he is concerned with a foundation planting that will not eventually hide his house, nor block out the entrance to the house.

Another definition is a natural one—what does nature define as a dwarf conifer? Mugho Pines in their native state range from low, nearly prostrate plants to some 30 feet tall, while the adjacent Austrian Pines will grow to 120 to 150 feet high. Nature has defined Mugho Pines

1. The source of the Cuttings.

     The condition of the plant from which the cuttings are taken makes all the difference to the success of the operation. The plant must be healthy and vigorous, and if extension growth is limited, the results will be poor.

2. Timing.

     This varies widely according to the species, and the season, but as yet we haven't taken any cuttings here before the 15th July, although with certain types, earlier propagation might be advantageous. Our most successful batches were with Betula papyrifera and Betula pendula ‘Youngii’ taken on the 18th August and 1st September. With Betula papyrifera it seems possible to take cuttings over a long period because

Witches'-brooms, while not common in pines, are such conspicuous objects as to be frequently reported. They have been observed in nearly all our North American species. They are also known to occur in this country on the European Scot's pine (Pinus sylvestris L.) and Austrian pine (P. nigra Arn.) and are reported frequently in European literature.

A small quantity of seed obtained from a sample of cones of the above tree was planted in 1950. The surviving population at the end of the growing season consisted of four seedlings. Three of the trees were normal appearing one year jack pines, but the fourth was much dwarfed resembling

The plant propagator has long been interested in ways to accelerate seedling development through proper manipulation of the environment. A number of researchers and commercial growers have reported on this subject in the Proceedings of the Plant Propagators' Society during the past seventeen years.

Conditions during germination and early seedling development exert a profound influence on the subsequent fate of the plant. Methods for improving these conditions, therefore, are of considerable importance to the propagator.

The recent development of plant growth chambers and other controlled-environment facilities affords today's grower a unique opportunity to control environmental factors previously neglected or poorly controlled.

In the past, controlled environment chambers were only available to the researchers (20). Although this is no longer the case (6, 9, 19), the literature on controlled-environment effects is still largely confined to non-economic plants. To fill

The propagation of horticultural plants is an important aspect of the nursery and bedding plant industry. Many species and cultivars are difficult or impossible to propagate from cuttings. Any technique that will increase the number of species which may be propagated, or reduce the time and space used for propagation will assist the industry.

The use of CO₂ may be helpful in propagation. Wittwer (5) and Voipio (4) reported strong root development of plants grown in an atmosphere enriched with CO₂. Carpenter (1) found that lettuce and chrysanthemum grown in a mist of carbonated water weighed three times more than plants from the check. At Morden, we found that when young vegetables and ornamental plants were grown in CO₂ enriched atmospheres a superior root system was developed. These observation led us to our propagation experiments.

One important concept must be understood concerning the use of

The most important method of propagating ornamental shrubs — deciduous as well as broad and narrow-leafed types of evergreens — is by cuttings (Hartmann and Kester, 1968). Likewise, many of the florist crops such as carnations, poinsettias, and chrysanthemums are propagated vegetatively by cuttings. Propagation by cuttings is simple, inexpensive, the techniques are easy to learn; many plants can be started in a limited amount of space, and genetic preservation of a desirable plant race is possible (Wott, 1966).

Water conservation is of prime importance to the cuttings during propagation and the development of mist propagation techniques greatly aided the propagation industry (Snyder, 1965). However, symptoms characteristic of nutrient deficiencies due to mineral nutrients leached from the cuttings or to nutrient dilution within the growing cuttings have been reported (Snyder, 1954; Sharpe, 1955; Good and Tukey, 1966). Nutrients can be applied to cuttings during

The following rather cursory introduction is to set the scene, so to speak, indicating how the tube came to be used as an integral part of Ontario's expanding forest regeneration program.

In brief outline, the tube-grown tree is one which has been established by sowing seed in a small tube containing soil. The plant must be tended and protected until it has developed to a stage where, it is judged, it may be transplanted with a reasonable hope of survival and satisfactory subsequent development. This paper deals with the tubes being used by the Ontario Department of Lands and Forests as part of its reforestation program. These tubes are three inches long and

Dr. S. H. Nelson, Head of the Department of Horticulture at the University of Saskatchewan, has some interesting unpublished data on removing different percentages of the leaves from cuttings. This work was carried out at Ottawa in conjunction with experiments on the spacing of cuttings. In general, his results are in agreement with

The use of chemicals to modify plant growth and development is rapidly becoming one of the most stimulating and exciting fields in horticulture. Chemicals have been found which will hasten or delay flowering. cause blooms to set fruit or to abscise, promote rooting of cuttings, kill undesirable plants and plant pests, and a host of other uses beneficial to the plantsman. B-Nine (N-dimethyl amino succinamic acid), a chemical which is commercially used as a growth retardant for florist crops, has been demonstrated to increase flowering and fruiting of tomatoes when applied at early stages of growth, while the same chemical can be used to eliminate bloom on the same plants when applied to the flower buds (2).

B-Nine was demonstrated to increase tuberous root formation (Fig. 1) when applied as a foliar spray to rooted dahlia cuttings. Cuttings taken from such treated plants rooted more readily than those from untreated plants or plants treated with Cycocel (2-chloroethyl

In 1961 two one-year-old grafted plants of a cultivar named Cedrus deodara ‘Kashmir’ were given to the Arnold Arboretum and since that time they have proven hardy.

DAVE PATTERSON MODERATOR: I'm delighted so many are here so early. I worried for two days that we wouldn't have enough questions; now I'm worried that we have so many we won't be able to cover them all. Without introductions of any kind I'm going to start right off with an easy question. What is the procedure for rooting Pinus strobus?

SID WAXMAN: I'm not going to give any recommendations as such but there are individual trees from which cuttings can be rooted. I know of one and have rooted cuttings taken in May wounded and treated with Hormodin 3 and Captan and placed in mist. They did take quite a while to root.

JOHN ROLLER: There are quite a few individual white pines that will root using Hormodin 2, mist and sand. I've noticed two Tanyosho Pines that in grafting it with moist peat around it, roots came out as quickly as the union is made. These were taken in early June from mature growth.

Timing of the propagation and the condition of the stock plants are most important, but the timing is the most important factor.

Usually the best time is from the middle to the end of April in this part of the country, and a very close watch must be kept on the stock plants. If the cuttings are taken too early, damping off in the mist will be excessive. The shoots must be taken at a stage when there are one or two pairs of well developed leaves, and when the shoot is making active extension growth. It is important that the cuttings are taken before the terminal bud is visible, and there is only a period of 7 to 10 days when hybrid lilac cuttings can be successfully taken. If taken after this period, rooting is slow and erratic. Particularly with this very soft type

There are a number of large well funded gardens across the United States and Canada which do an excellent job of displaying plants in

You may know by now that a British Region of I.P.P.S. has come into being and that we are to discuss this in the business meeting. As a prelude Dave thought it would be a good idea for me to try to tell you what a British propagator is. I must own this request set me back momentarily and when he went on to add that I was the only British propagator that many of the members had ever met, I was quite frankly stumped. So in order to get off the phone and finish my lunch, I agreed.

My first reaction was, of course, that there is no difference and fundamentally this is true. At the recent meeting which I had the pleasure of attending in England it was abundantly

The problem of scion varieties failing to make satisfactory growth when budded or grafted to certain rootstocks has been confronting nurserymen and growers for years. Grafting would seem to date back to antiquity. The early heterogenous combinations attempted were recognized as unsuitable in pre-biblical days (212) and also mentioned in early Chinese writings (43). The phenomenon of incompatibility, also known by the synonyms of uncongeniality or lack of affinity, has been common in a number of genera but more publicity has been given to fruiting trees, possibly because of the economic importance.

This survey was undertaken by the author for the International Plant Propagators' Society, Eastern Region, and partly financed by the organization. It was initiated by canvassing the membership, in both the Eastern and Western Regions. As shown in the bibliography, many usable returns were obtained, but the survey was supplemented to a large extent by a search of the

Potting

Potting should be done using a 3½ ins. clay pot which should have previously been crocked using a ¾ ins. Straight gravel. The compost should be a fairly light open mix, we at Hillier's use 7 peat, 4 loam, and 2 parts coarse potting grit to which has been added 4 oz. of John Innes base manure to each bushel of compost. No ramming is required so long as a few taps on the bench and the use of the thumbs are employed when potting.

After potting they should be stood down on a well drained open plunge. A covering of leaves or peat should be given to protect the clay pots from frost damage, also the size of the plunge should be banked-up either with sand or ashes, this not only protects the outside rows of pots from frost but also helps to steady them when personnel and trucks go up and down the paths of the plunges.

Spraying

Frequent spraying

A ready available supply of potting compost, either "John Innes", "Levington", or the "U. C. Soilless Composts"

I use "U. C. Mix D", to which is added slightly more lime for the general line of shrubs and ¼ in. shingle at a ratio of 1 part shingle to 3 parts U.C. mix. A medium grade of sphagnum peat is used throughout.

The jiffy pot used is No. 425, size 2½ ins. round × 3 ins. deep, the extra depth is an asset to shrub production.

Last but not least, a good supply of cutting material, which alas, is not readily available on most nurseries. It is a good idea and I feel, a must, if one is contemplating producing large numbers of shrubs in variety to have a "Stock Block" planted in the vicinity of the greenhouse or frameyard, with the required number of plants of each

To do this it is necessary to look at all the factors affecting the regeneration of plants from hardwood cuttings and by isolating each, determine its most