Volume 11

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Author: F.L.S. O'Rourke

PP: 16

Plant propagators serve both horticulture and forestry in the production of pines. Superior forms must be selected and multiplied, from seed if possible, if not, by vegetative methods. Whether the ultimate use is for utilitarian or for ornamental purposes, the objective is the same; to perpetuate the desired characteristics of a genetic strain or a selected individual tree.

Author: W.W. Osborne

PP: 57

Plant diseases become a limiting factor where plant propagation areas are used intensively. There are four general groups of causal agents of plant diseases; fungi, bacteria, nematodes, and viruses. Following are some pertinent characteristics of each of these disease producing organisms. Fungi - generally microscopic, filamentous organisms that reproduce by spores (seeds), commonly air borne. Spores produce germ tubes that may penetrate directly into the plant tissue or through natural openings or wounds, and cause infection. Bacteria -microscopic, one-celled organisms which cannot withstand desiccation. None of the plant disease bacteria produce spores, thus they cannot remain alive while being carried great distances in the air as can fungi. Bacteria enter plants through natural openings or wounds. Nematodes - Eel-shaped, microscopic organisms that may inhabit the soil in immense numbers. They require water for movement. Most frequently injury is caused by feeding in or on the

Author: Wallace A. Mitcheltree

PP: 67

"pH" means "potenz" Hydrogen or strength for Hydrogen. It is a German term devised by a German chemist to explain the measurement of acid in a media. pH is a chemical term and when one thinks in terms of Chemistry he must think in terms of Electricity and when thinking in terms of Electricity you think in terms of "plus" and "minus" electrical charges. We go back into our high school Physics, - we learned that there was a law in the study of magnetism that said, "Like poles repel each other and unlike poles attract each other". The same law holds in Electricity that "Like charges repel each other and unlike charges attract each other." Two magnets that are placed in such position that like poles are opposite each other repel each other and force one magnet away from the other. If the magnets are so arranged that the unlike poles are opposite each other, then there is an attraction and the two magnets are immediately attracted together.

In chemistry, for instance, water has the formula of H2O. If


Author: David G. Leach

PP: 78

When Sylvester March called me on the telephone and asked me to talk on the "Hardiest and Best Rhododendrons", I said sure, without giving it a second thought, and then it soon occurred to me that the best rhododendron are very seldom the hardiest. So in preparing the talk this morning it seemed the only thing that was reasonable to do was to define the regions and then say these are the best rhododendron that are hardy in each of these regions.

I am going to use for this purpose the U. S. Department of Agriculture Plant Hardiness Zone Map, prepared by Henry Skinner, which is much better and more accurate than the old map. We will have a quick look at novelties, all new rhododendrons introduced in the East within the last couple of years which are suitable for each of the principal hardiness zones in the principal parts of the United States starting at the Middle East climate and working up to the most severe.

Beginning with the Dexter hybrids, we will show a number of them. (Slides of


Author: Richard H. Fillmore

PP: 83

I wish to discuss briefly the rooting of a Cephalotaxus sport and I shall begin by describing the stock plant from which the various lots of cuttings were taken.

The cuttings for this test were taken from a plant of Cephalotaxus species growing on the grounds of the Sarah P. Duke Gardens at Durham, North Carolina. This plant is probably thirty or forty years old. It is about eight feet tall and six feet in diameter. Its main mass is stiffly erect with comparatively large, coarse branches. It would be generally unsuitable for the home grounds unless the home grounds were very large, but nonetheless, it has a place in a garden such as the garden which I am describing.

Very near the base it has developed a large fan-shaped spray of softer foliage with branches suggestive of a spreading Taxus species. This fan-shaped spray is probably five feet in circumference, and is readily traced to a single point on one of the main erect stems. It has probably developed within the last ten or fifteen


Author: H.R. Hurov

PP: 84

In the wet tropics there is a need for a method in which leafy cuttings of tropical arborials can be rooted directly in situ in containers or in the nursery row. Elimination of transplanting problems and excessive installation costs are the main reason.

Plastic Bags: A number of workers methods have shown that plastics can be used for propagating softwood cuttings. Among these Nichols (1958) showed that, in Trinidad, softwood cuttings of cacao could be rooted successfully in plastic bags. This prompted us to investigate the use of plastic bags in British North Borneo. Our investigations showed that plastic bags could be used successfully for propagating leafy semi hardwood cuttings from 96 different tropical arborials. Some of the more difficult rooting species rooted included: Mangifers indica, Hevea brasiliensis, Achras sapota, Lansium domesticum, Eucalyptus deglupta, Psidium guajava, Nephelium lappaceum, Artocarpus integra, Annona squamosa, Tamarindus indica, Cinnamonum


Author: John H. Kirch

PP: 86

Probably the most simple way of defining the chemical industry's role in the plant growth regulator field is to say that it is their responsibility to discover, formulate and market new compounds for man's use in regulating plant growth. More specifically, to the plant propagator this means providing chemicals that stimulate the formation of roots on cuttings, inhibit or stimulate plant growth, break seed or bud dormancy, control weeds, initiate the formation of flower buds and regulate fruit set or maturing.

Most people are aware that many new chemicals have been introduced in this field of plant growth regulators during the past twenty years. What is perhaps not too familiar to many are the methods used by industry to find these compounds. The remainder of this paper describes a method used by the author's company in its research toward finding useful chemicals in the plant growth regulator field.

This method involves three steps: 1) primary screening, 2) secondary screening, 3) field


Author: L.C. Chadwick, K.W. Reish

PP: 93

The remarks that I have this morning are going to concern the problem of the effect of wounding and synthetic growth substances on callus formation and the initiation of adventitious roots on American holly.

I think I should mention at the start that I want to give credit to Dr. Reisch, who supervised much of this problem, and to Donald Kling, who carried out many of the actual experiments.

The purpose of the experiment was to determine the effect of wounding and the use of synthetic growth substances on callus formation and on root formation on Ilex opaca, and perhaps more important, to study the anatomy of the origin of callus and adventitious roots.

I am sure that most of you are familiar with the literature that would indicate that wounding of cuttings of Ilex opaca have resulted in stimulation of root formation and also the fact that use of synthetic growth substances have also resulted in increased root formation. Some of the literature would indicate that wounding was perhaps


Author: Harvey Gray

PP: 95

Propagators and plantsmen dealing in ericaceous plants recognize the importance of fibrous, acid organic matter in the production of their crops.

In commercial production costly operations and organic matter must be recognized and reconciled with. Young plants either seedlings or cuttings, in their first and/or second year present no great problem nor cost, when grown in beds containing up to 50% peat. It's in the field product with plants in their second, third, fourth years that the organic matter requirement becomes a costly production problem.

Large quantities of organic matter added to mineral soils in an overall application is costly. Small quantities of fibrous peat to create an organic pocket for planting presents a costly operation if a uniform pocket mixture is to be created. It is here that the pocket mixer comes into play.

To make use of the pocket mixer for ericaceous plants, the mineral soil is first deeply tilled with a rotating tiller. One large shovelful of soil is


Author: Henry T. Skinner

PP: 96

The deciduous Ghent, Mollis and Knap Hill hybrid azaleas have found a restricted market in this country for two principal reasons: They are not as readily propagated as the semi-evergreen types and, though generally hardier, they are not as easy to grow in the average garden. Vegetative propagation of named clones is essential but many, particularly in Mollis azaleas, remain difficult to root from cuttings. As garden plants, too many selections, especially again in the Mollis types, are ill adapted to our eastern climate. In resenting our summer heat, they lack vigor or, if they grow reasonably well, they too often have poor habit or poor late season foliage too frequently disfigured by mildew. Not all selections have these faults, but many do. I have yet to see even a Knap Hill or Exbury hybrid which combines top quality flowers and flower truss with top quality habit, vigor, and clean, attractive foliage interestingly colored in fall - as it could - and as many semi-evergreen

Author: Robert L. Gonderman, F.L.S. O'Rourke

PP: 98

The Golden-rain tree (Koelreuteria paniculata Laxm) is a desirable small-sized neat landscape tree of unique merit for its lacy pyramids of yellow blooms in mid-summer and its persistent fruit capsules during the fall and winter. Apparently, there are few selected clones of this species and propagation by vegetative means is seldom practiced. Bailey (1), Creech (2), Fuller (4) and Hartmann and Kester (5) note that root cuttings may be used successfully and both Bailey (1) and Fuller (4) indicate that layering is also employed.

Propagation by seed is the usual method as the species is generally homogeneous and there is little variation among seedling trees. Fordham (3) states that a soak of 1 hour in concentrated sulfuric acid and immediate sowing of the seed resulted in germination within 13 days. The U.S. Forest Service (6) reports that 1 hour in sulfuric acid followed by stratification at 41° F for 90 days gave the best germination.


Author: Roy M. Nordine

PP: 22

The genus Pinus contains about 70 species that range throughout the Northern Hemisphere from the Arctic Circle to Mexico, the West Indies, and North Africa. This genus is the largest and most important of the coniferous group. They have long been very useful and valuable plant material for both large and small plantings, and unlike spruces and firs, their beauty increases with age, and they become more picturesque.

The usual plant forms, such as prostrate, globe, spreading, dwarf umbrella-like, columnar, pyramidal, weeping, and colored foliage are found in about a dozen species. Occasionally a new plant is found.

There are four very excellent books on conifers. One is by Murray Hornibrook: DWARF AND SLOW GROWING CONIFERS, published in London in 1923. This book lists and describes many forms that were found in Europe and now do not exist or, because of quarantine regulations, were never brought to this country. Another equally fine book is L. H. Bailey's CULTIVATED EVERGREENS,


Author: John L. Creech

PP: 101

The main objective of this discussion is to emphasize the significance of the origin of parental species material used in breeding programs for woody ornamental plants. We are inclined, frequently, to use a species as a parent without first-hand knowledge of the background of the material in relation to the extent of natural distribution of the plant or the variation that exists within the species. Some of these points are illustrated by the accompanying slides taken during an exploration for ornamental plants in Japan from April to July 1961. Rhododendron japonicum, R. obtusum var. kaempferi, and Camellia japonica particularly illustrate the great range of variation in habitat and plant habit of the woody plants of Japan.

Rhododendron japonicum inhabits the grass and scrub-wooded moorlands of Japan, including Kyushu, Shikoku, and Honshu. It does not occur naturally on Hokkaido although plants said to have escaped from cultivation are scattered in the hills around the city of


Author: James S. Wells

PP: 103

I don't know how far from propagation this association is going to allow its members to wander, but I think this is pretty far, and I hasten to add that I am not responsible for the paintings. I wish I were. The man who does them I had hoped would be here to explain the method by which he does the paintings.

The story very briefly is this: I go every summer to a little island off the coast of Maine for a holiday, called Monhegan Island. This last summer I met the man who does these paintings. He is a Dutchman with the unique name of Tecco Slagboom, a most charming and unassuming man, who lives for the most part of the year on the island in a little home way off from the crowd. He produces paintings of all kinds, but I was particularly taken with the clarity and fidelity of the botanical part of his drawings. I thought that in these days of mass production and kodochromes it was rather pleasant to see craftsmanship of rather a high order, and so I asked him if he would make three drawings


Author: William Flemer III

PP: 104

Like many other members of the Plant Propagation Society, I was greatly intrigued by Sidney Wasman's report in the 1960 meeting on his work rooting cuttings of Sciadopitys verticillata, which had always been a plant we considered impossible to root. We had always taken these cuttings in the mid fall, and although all cuttings calloused heavily and lived for long periods, they never rooted although we kept them in flats for up to one year. The sole result was a gradual enlargement of the callus. However, when we took cuttings in the late winter and early spring following Sidney's suggestions, the picture improved very greatly. This little report summarizes our results.

As Sidney noted last year, a great problem in cutting experiments with Sciadopitys is the very limited amount of wood available. Unlike working with Junipers or Taxus you cannot set up experiments with hundreds of cuttings for each treatment, and hence the results in this report must be viewed with some scepticism as


Author: Harvey Gray

PP: 106

The propagation house I am about to speak of is designed to produce ericaceous plants from seed or cuttings in a year-round program. The supporting frame is made of 1–¼" galvanized pipe and Lord and Burnham split tees.

The ridge, sash bar-rafters, eave and sill plates are home-made from rough cut redwood bench lumber. The lower section on the sides and end are enclosed with Johns Manville ¼" asbestos wallboard.

Four mil polyethylene is attached to 4 ft. wide sash. The sash is portable, made of fir 2 × 2's, treated with copper naphthalate, and covered with two layers of plastic with 1–5/8" dead air space between layers. The plastic is held in place with thin strips of redwood and tacker staples. The house is readily ventilated by the sliding sash.

A feature of the house is an upper and lower five foot wide center bed. The lower bed is for summer propagation, using either the vaporproof chamber or the mist system. The upper level is used for winter propagation.

The house is heated by


Author: Sidney Waxman

PP: 107

The use of artificial light in commercial nursery operations may soon become common practice. Some of you may recall the slides I showed several years ago of a flowering dogwood that grew nine foot tall in one year from a cutting by lighting it during the night.

Although getting plants to grow tall in a relatively short period of time has its value, there are many other purposes for which photoperiodic treatment can be applied. By using long or short day-lengths we can control growth of many, but certainly not all, trees and shrubs. Actually it is a tool that we can use to our advantage under various circumstances.

Before suggesting any of its applications there are several facts that I would like to discuss concerning the response of a plant to photoperiodic treatment.

First, many people confuse photoperiod with photosynthesis, the manufacture of sugar by the leaves in the presence of light. The production of sugars by the leaves requires a relatively high intensity of light in


Author: Roy M. Nordine

PP: 113

Witches'-brooms consist of thick bunches of small twigs emerging from one point on a normal branch. They may continue growing for many years and apparently do no damage to the branch or the tree. They are called witches'-brooms because it was once believed that the trees and shrubs bearing them had been flown over by witches on their nocturnal flights.

These abnormal growths are caused by fungi, rust, Black Mildew, virus mites, and other organisms. They have been reported from a large number of trees, shrubs, conifers, and herbaceous plants.

Dr. Henry Teuscher of Montreal Botanic Garden reported to the International Dendrology Union 1953 that some of these witches' brooms are caused by disease or insects, while others may be a bud sport. Teuscher reported that the witches'-brooms cannot be propagated by cuttings but must be grafted. He also reported that abnormal growths arising as a side shoot on a normal tree are the result of bud sporting and that they can be readily propagated from


Author: William E. Cunningham

PP: 115

To give you an idea of the procedure we follow in producing clematis, first some comment should be made on the way in which the stock plants are managed. Soon after the first of the year, one-year old plants are brought out of refrigerated storage and potted in 4" and 5" pots in a soil mix which is high in humus content, a mix in which drainage is good and wherein there is adequate texture to permit a free exchange of oxygen. Our potting mix is made up of fertile field soil and peat moss at a 2 to 1 ratio, plus about 10% sand or perlite.

The dormant one-year old stock plants are potted a period of several weeks to spread out the work load to alleviate the demand for growing space, and ease somewhat the demand for rooting space during the early spring season. We try to time the production of cuttings so that only about 20% of the total production occupies heated space in the early spring, with the greater proportion of the clematis production scheduled for the early and mid summer


Author: James S. Wells

PP: 119

The propagation of Chaenomeles does not apparently present any unsurmountable problems and the tests which I am about to describe will simply illustrate some of the finer points which can raise propagation results from a mediocre to an excellent level. The tests were carried out during 1954 while I was with the D. Hill Nursery Company in Dundee, Illinois, and they therefore apply to plants and conditions as they exist in the Midwest. The tests were made on numbered varieties of Chaenomeles raised by Dr. Colby at the University of Illinois, Urbana. These plants had been growing for many years in a stock block on the Hill Nursery and were well established. They normally grew quite vigorously and produced ample supplies of good shoots from which cuttings could be taken.


As usual, we were trying to test a number of things at the same time - a mistake, I believe, because one can become so confused in the multiplicity of tests that it is difficult to sort things out - but


Author: Case Hoogendoorn

PP: 123

Before I go into this subject I would like you to understand that I am no authority on Helleborus and I am going to tell you only my experiences with the limited variety we grow.

For the benefit of those members and guests who don't know Helleborus (also called Christmas Rose), I would like to tell you a little about this particular plant regarding its likes and dislikes so that you will understand more readily how we try to apply its proper environments to the propagation of this particular plant in order to grow it successfully.

To begin with, I would like you to understand that Helleborus is a perennial and because it is called Christmas Rose, it is not a rosebush as some people think.

We all know that Helleborus is a rather temperamental plant, but it is not too bad once you understand the plant. Helleborus is perfectly hardy as it originated from the Alps in Europe. It will never get winterkilled as it does not mind low temperatures at all but it might get summer-killed, as


Author: Seymour Shapiro

PP: 127

I think I should probably start out by saying the title which reads, "Experiences in Plant Propagation", is really very misleading. I think it is probably put in this way as a trap to make sure that you came back after the recess before lunch.

What I would like to do is discuss with you some of the experiments that you have been continuing along the same lines that I was working on in 1958. I have been concerned with working on some of the factors that control rooting. A plant very easy to root is Lombardy Poplar. The first question to ask is, why is the Lombardy Poplar so easy to root? The answer is a very simple one - it is very easy to root because the roots are already present in the tree at the time that you go out to take your cuttings. The root primordia in the poplars and in many of the willows are laid down as a normal feature of development of these particular plants and so they are already in the tree. All we have to do, then, is concern ourselves with what regulates the


Author: Aart Vuyk

PP: 31

Seed Source

I would like to go over a number of pine varieties grown in the northern part of the United States, beginning with Pinus sylvestris or Scotch Pine. Native in Europe to western and northern Asia, seeds from Spain and France have proven to be the best suitable strains for Christmas trees and ornamental purpose with good color and straight stems. Both strains are considered short needle pines. We also collect some seed in upper New York State, which is faster growing and with much longer needles.

Pinus strobus (White Pine) natural range from New Foundland to Manitoba south to Georgia, Illinois and Iowa, seeds from the lake states and upper New York are considered the best.

Pinus ponderosa, range from British Columbia, south to Mexico and east to Nebraska, Colorado and western Texas. We think seeds from the eastern rockies are the best.

Pinus mugo mughus (Mugho Pine) central and southern Europe seeds preferable from the Swiss Alps region.

Pinus nigra (Austrian Pine) central and


Author: Andrew T. Leiser

PP: 142

The old adage "there is nothing new under the sun" must, to quote another old adage, be "taken with a grain of salt". The fabulous fifties have had their impact on the nursery industry through the advent of plastic films. These are new. But it appears that many of the uses to which they have been put are refinements of old, old ideas. With the "old" as background we might review some of the uses of plastic houses, some of the problems and successes in the nursery field in order that it may stimulate a wider adoption of them for both propagation and winter storage.

L. H. Bailey (1) makes some interesting observations on the etymology of the word greenhouse and on the history of greenhouse construction and use. Dr. Bailey notes that the original meaning of the word was simply "a house in which to keep plants green during the winter." The plants were not expected to grow in these original "greenhouses" which may have started as a glass-walled portion of a dwelling. Ultimately separate


Author: John P. Mahlstede

PP: 148

Several months ago, without giving it much thought I accepted Dr. Synders' invitation to discuss the topic of the Dwarfing of Ornamental Plants By Grafting. When the time came to survey the literature associated with this subject, I found that he had restricted me to ornamentals. This means that we can come as close as the ornamental crabs, but not fruits, an area in which most of the dwarfing work has been reported. The title also restricted dwarfing to that resulting from grafting, which in turn eliminates a discussion of Bonsi, and the techniques associated with this ancient culture. To further complicate the preparation of this paper, I find that Dr. Karl Saxs' scholarly talk to this Society in 1957 summarizes the literature connected with this subject most admirably.

I would propose that we discuss the topic of Dwarfing In Ornamental Plants under the general headings of:

  1. History of Dwarfs
  2. The advantages and disadvantages of dwarf ornamentals
  3. Sources for dwarfing components
  4. Methods of

Author: Henry M. Cathey

PP: 154

Recently developed growth-retarding chemicals provide means for restricting the growth of many plants. They are useful in production and maintenance of plants of smaller size than those typical of the species or the cultivar. They also make it possible to use some species not now suitable for pot use and allow all plants to be fertilized and watered as frequently as necessary.

The leaves of all plants treated with growth-retarding chemicals are much darker green than those of untreated plants. This color is related more to the action of the growth regulator than to mineral nutrition.

Three chemicals have been extensively tested on many kinds of plants (2). These are Amo-1618 (4-hydroxy-5-isopropyl-2-methylphenyl trimethyl ammonium chloride, 1-piperidine carboxylate), phosfon (tributy1,2,4-dichlorobenzyl phosphonium chloride), and CCC (2-chloroethyltrimethyl ammonium chloride). The growth of most plants may be controlled by the proper selection of one of these chemicals. None of the

Growth Regulators in Relation to Plant Propagation

Author: H.B. Lagerstedt

PP: 204

I would first of all like to commend our program committee on their excellent choice for the evening's topic, Growth Regulators in Relation to Plant Propagation.

This subject, growth regulators, is a very timely one. It was, in fact, a timely subject 25 years ago when IAA was isolated from urine and found to be useful in rooting cuttings. It was even a timely subject long before that when sugar and oxidizing agents were being investigated as rooting aids. It will no doubt be a timely subject 50 years from now, even though plants will have yielded up more secrets about themselves than we presently know. Perhaps, thinking of it in this way, Growth Regulators in Relation to Plant Propagation should better be described as a timeless subject.

At the present time we are probably on the threshold of propagation discoveries nearly equaling the period of the mid-thirties. Perhaps this evening we will catch a glimpse of what is currently going on in propagation as well as what the future may hold

Plant Hormones

Author: J. Van Overbeek

PP: 205

In the plant, as well as in the animal, minute amounts of chemicals regulate the growth process. These compounds are called growth regulators, and if they are naturally-occurring, they are spoken of as plant hormones. At present we recognize major classes of plant regulators:
The Auxins.
The Gibberellins.
The Kinins.

We will discuss what they are, how they regulate the plant's physiology, and to what practical uses they have been put.

The Use of Growth Regulators in Propagating Clonal Rootstocks for Several Tree Fruit Species

Author: H.T. Hartmann

PP: 208

Clonal rootstocks are becoming more important each year in propagating many kinds of fruit trees. Such stocks have the advantages of uniformity, perpetuation of specific, desired characteristics without change, and often result in more rapid propagation time than when seedling stocks are use. They have the disadvantage, however, of perpetuating diseases ?- so the use of initially clean stock is very important.

During the past few years in California, a definite need for clonal rootstocks, and rapid methods of propagating them, has arisen in several tree fruit species.

As a rootstock for the English walnut, Paradox walnut seedlings (Juglans hindsii × J. regia), resulting from natural crossing, have proved to be excellent, better in many instances than the usual J. hindsii seedlings. However, certain Paradox seedlings are far superior to others in vigor, resistance to nematodes, and to oak-root fungus. A method of developing clonal rootstocks from these certain seedlings would be of great

Growth Regulators, The U. C. System, and the Oki Nursery

Author: George Oki

PP: 215

A great deal of emphasis has been placed on rooting hormones since 1935. This, however, did not mark the beginning of the use of hormones. it has been said that Dutch propagators inserted a wheat grain into the split basal ends of cuttings over a century ago.

The wheat grain in germinating, releases an auxin, thus stimulating root growth. Auxin is another term for natural hormone produced by plants. Growth regulators as we know them today are synthetic auxins, with a purpose in mind, "to stimulate root growth".

Although auxins, or hormones, play a very important role in propagation today, there are many other factors equally, if not more important. In the preface of the University of California Manual 23, edited by Dr. Ken Baker, is a symbol of the U. C. System. Within this symbol, with a few minor changes, lies the identical basic rules of plant propagation. The changes are:

Progress in the Production and Distribution of Registered Stocks

Author: Curtis J. Alley

PP: 219

Certification programs are not new. G. H. Berkeley, speaking at the 14th International Horticultural Congress in 1955, reported that Canada probably had one of the first certification programs. It was inaugurated in 1915 in Ontario for the certification of seed potatoes. Previous to this (1910) Ontario attempted to control certain stone fruit viruses, such as those which cause peach yellows, little peach, and "X" disease of peach by requiring annual inspections of orchards. In 1924–25, certification of virus-free red raspberry planting stock was initiated. In 1947 a certification program was started for virus-free cherry budwood based on an indexing procedure. The States of Washington and Oregon have informal certification programs for virus free cherry trees. J. A. Milbrath reported on such a program at the Oregon State Horticultural Society meeting in 1947. At first the program was very successful, but it gradually deteriorated because of lack of proper maintenance for virus-free

Author: Walter D. Kraus

PP: 223

It has been our privilege and opportunity to work very closely with Dr. Curtis Alley and his associates and the State Bureau of Plant Pathology in the establishment of Certified Increase Blocks of cherry varieties, grape varieties and rootstocks. We were inexperienced in how to convert and apply these new phases of science to a commercial and practical enterprise, integrating them into our production of nursery stock. The University of California, and the Bureau of Plant Pathology, and the Nursery Service, California State Department of Agriculture, have given their undivided support and assistance, for which we are very grateful.

Dr. Alley has informed us of the development and importance of registration and certification of plant material, and I would like to review with you what we are doing with this material, how we maintain such plants, and the inspection of these Increase Blocks and last of all, the very important point, the acceptance of such nursery stock by the commercial

Progress in Bringing Nomenclature of Western Ornamentals Into Conformity with the International Code of Nomenclature for Cultivated Plants

Author: Wray F. Hildabrand

PP: 226

The California Department of Agriculture and the County Agricultural Commissioners are interested in this subject for several reasons. (1) One of our objectives, which is shared with the nursery industry, is the production of high quality nursery stock in California. (2) We have a law to enforce which requires that plants be labeled correctly when sold. (3) We have some good friends in the business of growing and selling plants and we would like to see them get ahead. Good merchandising practices such as adequate labeling should help.

The International Code provides the guide lines for the correct naming of plants and sets a standard for the industry, as well as for regulatory agencies in enforcing laws pertaining to plant names.

Through need and experience, most industries have established standards for the products they handle. These standards may be voluntary on the part of industry members or may be established by law. When legalized it helps eliminate unfair competition. A


Author: Hoy C. Grigsby

PP: 33

My interest in learning to root the pines came through work in forest tree improvement. We propagate vegetatively to test the heritability of certain features of superior phenotypes. Once selected, trees have proved their ability to pass along desirable traits to their clonally propagated offspring, they are multiplied to obtain material for seed orchards.

Pines are often propagated by grafting, and with considerably more success than by rooting. Grafting, however, has some drawbacks that would make rooting, when perfected, more desirable. Sometimes stock and scion, are incompatible. If a tree's superiority is due to its root system, this superiority will be masked when the scion is grafted to the rootstock of an ordinary tree. A reasonably successful technique should make rooting cheaper than grafting.

The following techniques are the ones found most successful with loblolly pine (Pinus taeda L.) after seven years of research involving trials with more than 15,000 cuttings.



Author: Elizabeth McClintock

PP: 229

Plants have names for the same reason that persons and objects are named, simply as a means of referring to them. Long before our present civilization came into being, people who lived in a particular area or region of the world had their own names for the plants they knew and used. The Aztecs, for instance, had medicinal uses for many of the plants in their area and they had their own names for them.

The naming of a few plants in a local region, however, is quite different from the situation which exists today when we are dealing with many thousands of plants on a world-wide basis. There are probably between 200,000 and 300,000 species of ferns and seed plants known today. These are contained within about 10,000 genera and 300 families. Of these 200,000 to 300,000 known species, about one-tenth or 20,000 to 30,000 species, are cultivated. I have not located exact figures but Hortus II, published in 1941, lists over 18,000 species cultivated in North America.

The naming of cultivated


Author: Fred H. Petersen

PP: 235

Without prescribed systematized methods, the production of any item of commerce, be it an intercontinental ballistic missile or Juniper Tam, could be a chaotic unpredictable, uneconomic and unrewarding procedure. The pressing need of a guide for the systematic production of nursery stock was seen several years ago by Dr. Kenneth F. Baker in the Department of Plant Pathology at the University of California in Los Angeles. The outgrowth of this awareness was the UC Manual 23, The UC System for Producing Healthy Container Grown Plants.This Manual, edited by Dr. Baker, provides practical guides and a realistic basic philosophy upon which many present-day successes in the California Nursery Industry are based. The authors, both explicitly and implicitly, convey the thought that systematized growing and the adoption of standardized methods and procedures can lead to the production of nursery stock with a higher degree of standardization than some thought ever possible. The successes of

Author: Paul W. Moore

PP: 240

The objective of the reliable citrus nurseryman is to produce trees which are typical of the variety, have a high yield potential, and which will be long lived. To accomplish this requires a thorough knowledge of variety and strain characteristics, careful scrutiny of budwood sources for mutations, acquaintance with the known virus diseases which affect production and longevity, and a knowledge of rootstock-scion interactions and adaptations.

The prosperity and success of the citrus industry, and the financial solvency of individual growers, depends in no small measure upon the integrity, the knowledge, and the sound judgment of the nurseryman.

During the last three years over 5 ½ million citrus trees have been grown for planting in the commercial orchards of California. Every one of these nursery trees consisted of two parts, scion and rootstock. The scion variety was chosen first for the variety - such as orange, lemon, tangerine, or grapefruit, and secondly, as a particular


Author: V.T. Stoutemyer

PP: 252

The subject of light in propagation is an example of a badly integrated field of knowledge with a conspicuous lack of communication between the workers in basic science and those who represent the applied side of agricultural science and technology. It is also an example of a rather haphazardly worked basic field with many conspicuous gaps in our knowledge. It is difficult to explain why researchers have given so little attention to some of these problems. One example is that almost no information is available on the effects of different light qualities and intensities on the stock plants for cuttings. The voluminous literature on the influence of light on seed germination is somewhat confusing for reasons which will be discussed later, although the rapid progress of recent research is clarifying the situation.

We shall treat four main subjects in our discussions of light. These are:

  1. Light and seed germination.
  2. Effects of light on stock plants for cuttings.
  3. Light and the rooting of cuttings

Author: A.A. Piringer

PP: 261

Plant scientists have known for over 40 years that the length of day controls many phases of plant growth and development and this control has been called photoperiodism. Since the phenomenon was discovered in 1920, they have learned through systematic experimentation which plants flower or grow best on long days and conversely which like short days best (1,2,3,4,5,6). Later, they learned that the response depends on the daily duration of darkness. If the middle of a long night was interrupted with some white light, the plant responded as though it had received short nights, hence long days. Since white light is a mixture of many colors, one wondered whether any color controlled plant growth and lowering more effectively than another. When plant physiologists tested the responses of plants to the various pure colors, they learned that red was most effective. Subsequently, they also found that many kinds of plant responses other than flowering were controlled in much the same

Author: Roy M. Sachs Chas.F. Bretz

PP: 266

Piringer (6) has reviewed the main discoveries showing that growth and development in woody plants are greatly dependent upon day length. We have been particularly interested in commercial application of these findings.

Some parts of coastal Southern California are noted for relatively mild spring and autumn temperatures, perhaps suitable for optimum plant growth and generally considered to have a growing season of 250–300 days (9). Optimum day lengths , however, prevail for no more than 90–120 days of that period; indeed, most species make the major portion of growth during late May to early September. Thus, it might be expected that supplemental lighting that creates summertime (greater than 14 hours) day lengths throughout the "growing season" might have great value in promoting the growth of nursery plants--perhaps to the extent of doubling the growth per year of many species.

In our initial experiments at and around the University of California at Los Angeles, these exciting


Author: Edward F. Frolich

PP: 277

Webster defines the term, etiolation, as "to blanch by the exclusion of sunlight". This is hardly an adequate definition when applied to this particular discussion. A better title might be "the inhibiting effect of light on the production of root initials". This effect differs somewhat from those in the preceding discussions in that here we are interested only in the light falling on the actual tissue that is to produce the root initials. This, in ordinary nursery practice, would be the tissue at or near the base of the cutting.

There are statements in the literature that mention was made of the beneficial effects of darkness on rooting of apples as early as 1537 (2). Since that time there have been several papers describing the use of this technique for rooting cuttings of several different kinds of plants. Plants vary widely as to their ability to produce root initials when exposed to light. Many plants, of course, must be not at all, or only slightly, inhibited by light in the


Author: R.M. Endo (Presented by Philip A. Chandler)

PP: 284

In California, the Guinea Gold Vine, Hibbertia volubilis, is affected with mosaic symptoms so commonly that not a single healthy plant has been observed either in home plantings or nurseries. The Guinea Gold Vine is native to Queensland and New South Wales, Australia, where it grows as a prostrate or twining shrub with solitary yellow flowers. In California it is grown primarily in the cool, coastal areas where it fails to produce seeds; thus vegetative propagation is necessary and is suspected as the major factor responsible for the high incidence of mosaic-affected plants.

Recent studies at UCLA indicate that the disease is caused by strains of the cucumber mosaic virus (CMV), and that the widespread occurrence of the disease is probably due to propagation of diseased cuttings from infected plants. Shoots free of CMV were rather readily produced by growing diseased plants at temperatures averaging 90°F for 3 to 12 weeks. Symptom-free shoots were removed from diseased plants, and were


PP: 285

This session - the Plant Propagator Question Box - convened at 7:30 p.m. with Mr. Percy Everett, Rancho Santa Ana Botanic Garden, Claremont, California, as the moderator.

Author: Dennison Morey

PP: 300

Last night as I was putting the finishing touches on my introductory remarks I suddenly realized that I had assumed an obligation that was going to be difficult to fulfill. In moderating the final symposium I have accepted, at least in principle, the responsibility for trying to pull things together. Since we are going to deal with practical solutions to difficult problems, my task as I see it, is to try to provide some basis for integrating the vast amount of knowledge which has been presented to us here so far so that it can be evaluated on the basis of experience. This is not an easy thing to do. We have had a unique privilege here. We have stood on the frontiers of science with genuine pioneers, a rather hazardous place for green troops, as the inadequacy of some of my own questions attest.

Fortunately, my prepared remarks seem to be still appropriate. I feel that a tremendous volume of fundamental information has been presented at this Conference. If all of this information is


Author: Hans Hess

PP: 35

The Program Chairman very kindly allotted me ten minutes to talk on the grafting of Pines. I believe this is about eight minutes more than is necessary to cover this method of production which is rapidly growing extinct.

A few more years experience with mist propagation and some new additions in the field of root inducers and inhibitors and all of us old grafters are going to be without a trade.

There is only one reason for producing Pine Selections by grafting; up to this time no better or cheaper method has been found. What are some of the Pines reproduced by grafting? All of the selections of White Pine, the fastigiate, the pendulous, the globe and dwarf form, the various selections of Scotch Pine and also Swiss Stone Pine. This last Pine can be grown from seed, however, it is a very slow process and the variation in the seedlings is considerable.

The various Pine Selections that are being grafted today are either sports which are quite common among seedlings or the result of


Author: Julius Gorman

PP: 304

Juniperus chinensis torulosa is an upright juniper. It's common name in Hollywood juniper - it has vigorous growth. The plants are hardy and will take considerable cold weather; they like to be grown in sandy, loamy soil, but are really not particular. They also like a sunny location. They can either be propagated by grafting or cuttings. Grafting is expensive so that's why the Leonard Coates Nurseries started trying to root them from cuttings. We tried them the regular way, just putting them in a greenhouse with bottom heat, but had very poor luck. In October, 1959, we started a couple of flats which were put directly outside, with the idea of stimulating rooting by letting them stay outside for some time. But then we noticed callusing on the cutting in about three or four months, so we decided we'd do a little experimenting with them. We took them back inside- to the potting shed- and treated them with Hormodin 3 and put them this time in the greenhouse with bottom heat and the they

Author: W.M. Tomlinson

PP: 306

Juniperus conferta, commonly called Shore juniper, was first introduced into the nursery trade in 1915, its native habitat being Japan. The Shore juniper obtains a maximum height of 18 inches and usually has a spread of between four and five feet, making an informal mat of blue-green foliage.

This juniper is one of the best low-growing ground covers for sea shore or dry, sandy situations in the coastal areas. It will with-stand salt water spray, and even some submersion, exceedingly well. It also has been used quite extensively the past few years in rock gardens and mound plantings. The Shore juniper grows best in full sun and withstands most coastal and inland weather conditions. Through our past experience, however, we have discovered that it will not grow in the hot desert areas of our state.

In the propagation of Juniperus conferta in Southern California, we have found that cuttings taken from the middle of December to the middle of January root much faster and in higher


Author: Gerd Schneider

PP: 309

Ceanothus griseus horizontalis, ‘Yankee Point’, originated as a variant in a population of about four thousand seedlings. The seed was collected in the native stand of Ceanothus griseus horizontalis at Yankee Point, south of Carmel, California.

This clone grows about 2–3 feet in height and spreads as much as 8 feet. If planted on level ground, the plant will reach its greatest height at the center, and the side branches gradually slope toward the perimeter of the plant, almost describing a circle. If planted on a slope, the branches will follow the structure of the terrain, often exceeding 10 feet in spread but not more than 12" to 16" in height.

The color of the flower is a deep blue, surpassing by far the flower quality of Ceanothus horizontalis, ‘Hurricane Point’. The blooming period extends from March to May. Ceanothus ‘Yankee Point’ tolerates a wide range of environments. A sandy loam soil with good drainage and, in the inland areas, partial shade provide good garden growing conditions.


Author: F.S. Olsson

PP: 314

Cutting Materials: Wood for cuttings should be taken from healthy plants that have attained a spring growth of 6 to 8 inches. Remove the soft tip down to the first mature leaf, then begin taking cuttings down the stem. We cut the leaves in half but that's mainly because we stick 400 to the flat.

Hormone: Hormodin No. 2 - we have had very good results with this. The media is 3 parts Sponge Rok, one part peat moss mixed with water in a tub. The media is packed around the edges of the flat and leveled off. The cuttings are placed in intermittent mist house. Our largest house is 100 feet long, with a capacity of 150,000 to 200,000 cuttings. The house has 50% saran shade on top, a 6 mil. polyethylene on that. One wall is nine feet, the other wall is six feet high. We leave an opening on the highest wall in the summer so the heat can escape. In the winter it is completely covered. The mist is controlled by two 5-minute timers, one for each half of the house. They are connected to a 24 hour


Author: Martin Usrey

PP: 316

In the propagation of Convolvulus cneorum (Morning glory bush)we have tried taking cuttings at different times of the year; however, the nature of the plant is such that the wood is always soft. Consequently, the cutting is made a little longer than it would be otherwise in order to get into firmer wood. Cuttings are made about 5" long, with the basal cut made just below the node.

The best times for the propagation of this plant was found to be at two different months in the year - April and September, although cuttings made at these still gave erratic results; some years very good, but in the years only fairly good. When the cuttings were made at other than times mentioned, the results were also erratic, but response was usually poor.

The "hormone" we use is Hormodin No. 1 because the condition of the wood necessitates this concentration. Results have been poor where higher concentrations were used. The cuttings are stuck into a 2 parts Sponge Rok (perlite), 1 part peat moss mix when


Author: Carl Schmidt

PP: 318

Of the many existings varieties of Ilex aquifolium I have, for the purpose of this discussion, selected the variety commonly referred to as French, English, or Blue Stem English holly. Also, botanically speaking, this is probably not a true variety: this group of hollies produces trees of quite distinct qualities, marked by excellent foliage and berry characteristics. This is variety most widely planted in the commercial holly orchards of the Pacific northwest (1) and it is the one that we have used mostly in our own holly orchard at Point Reyes, and from which we are propagating for the nursery trade. Due to the fact that this type of holly produces, at an early age, large amounts of parthenocarpic berries (that is, berries with sterile seeds)it is sometimes referred to in the nursery trade as "self-fertilizing" and thought of as "bi-sexual". However, to the best of my knowledge, all Ilex aquifoliumare strictly dioecious plants, which require pollination by male plants for fertile seed

Author: John Spaan

PP: 36


Probably the most blame for failure of the grafts can be traced to the condition of scions at grafting time. Scions should be taken only from the season's new growth, and must be made of firm, semi-mature wood.

While several Pinus sylvestris types produce fairly even textured new growth, others have variable states of growth, containing both firm and soft wood over a period of time. Pinus sylvestris fastigiata is very good for an even supply of scion wood, while many types of Mugho pine vary as much as 6 weeks or more. Scions should be 2-½ to 3-½ inches in length, and all needles, excepting one inch at the top, removed. Fifty or sixty scions at a time can be prepared, for the operator to carry in a container under a damp cloth.

The side graft method should be used when grafting pines at the ground level in nursery rows this time of year. Since the scion must always be placed on the north side of understock, the rows of understock should be planted in north to


Author: Kenneth B. Fisher

PP: 39

There are a limited number of perennial plants that can be propagated by root cuttings. However, throughout the country there are many thousands of plants produced by this method, since among others, Oriental Poppies and Phlox decussata are handled in this manner.

Perennials that are to be propagated by root cuttings, are no different from woody plants in that their roots must be capable of producing shoots. Such shoots are developed from latent (dormant) buds laid down in the initial period of growth, or from adventitious buds formed after the root cutting has been made. Such adventitious buds usually occur in the larger portion of the roots, closer to the crown of the plants.

Generally speaking, in our area (Lake County, Ohio) root cuttings are made in late fall or early winter. For this purpose the desired number of plants are dug in late fall and stored in a cold frame or similar place, until the propagator is ready for them.

The one exception is Oriental Poppies (Papaver


Author: William Flemer III

PP: 42

The root cutting method of propagation is one of the least frequently used of all the methods of vegetative propagation. The primary reason for the relative rarity of this method is that the plants for which it is the best technique are infrequently grown in the average nursery. A secondary reason is that it is relatively inconvenient to secure the cuttings. Either the whole plants to be propagated must be dug up to secure suitable roots for propagation, or else the soil around stock plants must be excavated to expose the roots prior to their removal, at best a rather tedious procedure.

Despite the difficulties involved in securing propagating material, root cutting propagation is by far the best method for increasing certain special plants which will not root from stem cuttings. It is also useful for increasing certain clonal varieties of plants which do not come true from seed, do not bear reliable seed, or are staminate clones of dioecious genera. Here are a few examples of plants


Author: C.E. Hess

PP: 51

Following the discovery of four root promoting substances in the easy-to-root juvenile form of Hedera helix. L. and the red flowering Hibiscus rosa-sinensis. L. (2), a procedure was developed to isolate and purify the substances in larger quantities. The rooting cofactors will be referred to by numbers, ie., cofactor 1, etc. The basis of the numbers was the relative position of the cofactors on a chromatogram developed in isopropanol and water (8:2 v/v) solvent system. The R values of the cofactors in this solvent system were as follows: cofactor 1, 0.0–0.13; cofactor 2, 0.33–0.53; cofactor 3, 0.60–0.73; and cofactor 4, 0.80–0.93.