Proceedings Library

One of the characteristics of the juvenile, non-flowering phase of Hedera helix is its striking ability to form adventitious roots on the stem of intact plants. In contrast, the adult flowering phase of this species does not form aerial adventitious roots and is difficult to root when leafy stem cuttings are placed under favorable environmental conditions (7). Many observations indicate that cuttings of most plants in the seedling (juvenile) state initiate roots more readily than in any other stage of development.

It has been known for many years that auxins stimulate adventitious root formation (13, 17). However, cuttings of many difficult-to-root plants, including the adult phase of Hedera helix, respond very little to auxin treatment (2, 9). There is evidence that endogenous factors, other than auxin, are important in the control of adventitious root initiation (4, 7, 8, 9). More specifically there is evidence that phenolic compounds such as catechol, pyrogallol, caffeic

The objectives of the experiments reported in this paper were to find methods of producing bulblets under aseptic conditions and to increase the efficiency of bulblet production from scales. Accomplishment of these objectives would increase the commercial feasibility of multiplying and maintaining pathogen-free stocks and also increase the rate at which planting stocks of new cultivars could be built up.

In performing these experiments, bulb scales of Lilium longiflorum ‘Croft’ about 1.5 cm wide and 3.0 cm long were used. ‘Croft’ is a cultivar

Propagation by hardwood cuttings is, no doubt, the simplest and least expensive method of vegetative propagation. It would be most desirable to be able to extend this type of propagation to a much greater range of plants. It would be particularly desirable to be able to utilize hardwood cuttings in place of the more laborious layering methods now widely used in propagating clonal fruit tree rootstocks and other difficult to propagate plants. Furthermore, hardwood cutting propagation procedures lend themselves readily to mechanization practices which are more and more being utilized by the nursery

The purpose of the experiments reported here was to evaluate rooting of different Prunus clones. To do this we wanted to develop a screening procedure whereby we could accurately and easily evaluate the genetic ability of individual clones to initiate roots. We also wanted to distinguish "rooting

In the past all smoke trees had been propagated by grafting, but a shortage of understocks, and the tendency toward weak graft unions, prompted a consideration of rooting of cuttings.

In January, 1966, the first cuttings were stuck in pure sand in a heated greenhouse with a bench temperature of 70° to 72°F. One hundred cuttings were put in a regular cutting bench, and another 100 were placed under intermittent mist. All were terminal cuttings. Most cuttings leafed out, but those in the regular bench failed even to callus. Those under the mist lasted longer, and a few rooted, but the roots decayed before they were ready to dig.

In December, 1966, a cutting bed was built in an unheated poly

1. Source of the cutting material
2. Timing — when is best to take cuttings
3. Preparing the cuttings
4. Treatment of the cuttings
5. After-care of the cuttings

In 1960, Dr. Hudson Hartmann and Prof. Carl J. Hansen reported that ‘Old Home’ pear (Pyrus communis), is a valuable rootstocks in combating pear decline and fire blight. Cuttings can be rooted if taken in November with the bases soaked 24 hours in 200 ppm IBA, packed in moist, not wet, peat moss and placed at 65° to 70°F. These root in 3–4 weeks and can then be planted immediately in the nursery, weather permitting. If stored at 40°F., only 1/3

Tree age. Tree age is probably the most important factor in rooting pine cuttings. Watanabe (26) reported 4, 17 and 30 year Pinus densiflora rooted 62, 42 and 30% respectively. Kummerow (10), reporting on rooting needle bundle cuttings of P. radiata, found average rooting percentages for 1–3 year trees as 24.7%, for 7–9 year trees as 19.5%, and for 28 year trees as none. An even earlier loss of juvenile rooting

We keep accurate records of our seed collections, time of year, location, etc.; but, despite this information, it is interesting to note that each year our timing appears to be astray, and it is usually necessary to return to the site for further inspections of the new crop of seeds before collection. These extra trips usually prove fruitful, although in some cases very time-consuming, especially if we are collecting natives from high elevations, such as the huckleberry oak, Quercus vaccinifolium, or the pine mat manzanita, Arctostaphylos nevadensis. The current season at

Seeds selected for our tests were Arbutus menziesi (Pacific madrone), Mahonia nervosa (Cascade mahonia), and Cornus nuttallii (Pacific dogwood). It should be noted here that for the first two plants there is no problem if more than one seed were to germinate in a pot. Therefore, in the case of arbutus and mahonia, two to three seeds were used per container, but only one per pot for Cornus nuttallii.

Two types of containers were used: (1) 2½" × 3 1/3" peat pot filled with a standard potting mix, and (2) Jiffy "7's", which are basically a fertilized peat contained in a plastic net. Both the peat pots and the Jiffy "7's" were placed in standard 15 × 20 in. nursery flats to facilitate production seeding. An assembly line was set up on roller conveyers. Peat pots were filled at the potting bench,

Two years ago I changed procedures and have been following closely a more exact method of handling the seeds and seedlings of this plant. The seeds are picked as soon as they are pipe and spread out on newspapers in the greenhouse bench for a day or two. The wings rub off more easily with a little drying.

A standard flat is filled with a mixture of ½ peat and ½

One of the externally visible effects on etiolated stems is blanching, resulting from the disappearance or lack of chlorophyll. Etiolation is sometimes defined in terms of this blanching effect, but in relation to propagation, the presence or absence of chlorophyll in the stem probably is of no significance.

Etiolation is generally thought of in relation to deliberate exclusion of light during stem development, or for a period of time prior to the rooting process, but exclusion of light in the normal procedure

Only in recent years has the propagation of maples from softwood cuttings become practical. Two new techniques, the use of controlled mist and the availability of polyethylene plastics, have made this possible. The use of controlled mist in rooting softwood cuttings is not new, but its use on a widespread scale is. When a polyethylene cover is used, mist is unnecessary.

Tree anemone, Carpenteria californica;

We are located in northeastern Oklahoma in the Cookson Hills approximately 50 miles west of Ft. Smith, Arkansas. The average minimum temperature is 5° to 10° F. below zero. However, overwintering in our area is further complicated by rapidly fluctuating temperatures, with highs in the 70° F. range sometimes being only 24 to 36 hours ahead of the extreme low temperatures. Therefore, most broadleaf evergreens grown in containers, such as pyracantha, euonymus, holly and the soft varieties of deciduous shrubs are subject to varying degrees of winter damage. We felt that polyethylene-covered houses offered the most promising solution, but several criteria had to be considered:

1. The houses had to be low in cost.
2. They had to be able to hold snow loads of 6 to 12 inches.
3. They

Easy accessibility around, to, and in the greenhouse must be provided for this equipment. Roads and walks inside and around the greenhouse should be either blacktop or concrete. The first is the least expensive, but gives some problems resulting from the weight of heavy equipment and from its softness during warm weather. The packing shed, too, should be completely surfaced.

Inside most new pot plant greenhouses the benches run crossways with a wide access aisle going the long way. As an example, a 37½ foot wide house may have a 5½ foot aisle and 32 foot long benches. The 5½ foot aisle provides enough space for an electric cart. Between the houses, a sheet of plastic is sometimes used to help control the

All of our production is grown in standard southern California nursery flats, which are approximately 18 inches square and 3 inches deep. To us the unit of production is a flat, not a single plant. Most flats are planted 100 plants per flat although some have as few as 48 depending upon the plant and the specifications for a particular job

Almost all of the material we grow from cuttings or divisions are rooted and sold in the same flat without transplanting; seedlings are started in seed flats and transplanted Most varieties we grow are ready for sale in 30 to 90 days although a few slower growing types may take up to 120 days. Since most of these are grown quickly, it means that they

GERMINATION OF SEEDS — About 350 B.C., Theophrastus reported that germination of rose seed was very slow and erratic so that, in order to avoid delay, cuttings were made. Some 450 years later, Pliny mentioned that rose seed germination was a very slow process. Here am I, about 2,300 years later, agreeing with both these learned gentlemen and one wonders just how slow progress can be!

The so-called "seed" found in rose hips is really a fruit and in many species, such as Rosa canina, such "seed" lies dormant for many months before germination takes place. If it were possible to control this dormancy, one would be nearer to being able to control the plant density in the field which, in turn, should lead to more uniform rootstock production.

Source of Seed — For the current work at Luddington Experimental Horticulture Station, homeproduced seed is being used. The seed from different bushes of wild R. canina is likely to behave differently,

Production for our retail trade is geared towards the propagation of a vast range of plants, generally in fairly small numbers, whereas the wholesale grower is normally engaged in the production of a fairly small range of plants in vast numbers. If the business is entirely orientated towards a garden centre, or more than one garden centre, or if it is a wholesale business

Propagators spend much time ‘multiplying by division’, often into quite small pieces of parts of shoot, root or leaves, which they then place in situations where they grow to wholeness once again. There are many hazards in these processes and the greatest of these is desiccation or drying which, carried too far, is certain death. Herbaceous leafy cuttings are the chief sufferers but root cuttings are in the same danger, though the damage may not be immediately obvious. There is a tendency today to rely upon recovery under mist, but a wise man takes reasonable precautions. Moist-lined containers should be used for the collection of vulnerable cuttings. Polyethylene is suitable provided it is completely shaded whilst in use. Very full polybags may lead to suffocation of active cuttings; partial filling and

With the help of several graduate students, we have been attempting to establish a morphological time scale for predicting rooting potential in certain woody species, and to correlate physiological condition and developmental events with shoot rootability (1, 3). We have had some success, and have changed many of our ideas, but much remains to be done. In the beginning, it was our concept that seasonal changes in shoot rootability were associated with tissue and physiological

The structure is built on the railway sleepers placed in two lines 17 feet apart, outside measurement. The curved Nissen hut irons, consisting of two 10-foot lengths, and one quarter-length of 2 feet, 6 inches, are welded together to form one arc of 22 feet, 6 inches. The angles on the irons are used to bolt to the sleepers with coach bolts.

These iron "ribs" are 6 feet apart and distance pieces of six-foot lengths of 2-inch by 1-inch timber keep them at this distance. Wires (10 gauge) are run the length of the house, threaded through the holes which are already in the centre of the irons. In the end irons an eye-bolt is used to strain the wire taut.

Nylon net is then stretched over the frames and secured to the sleepers by staples at the sides and ends. The plastic is then stretched over the frames and held down

Group 1. In this group I include the following species — Daphne collina, D. × hybrida, D. odora and its varieties, D. retusa, and D. tangutica.

The time for taking these cuttings is late July to the end of August but the all-important factor lies in taking them when they have reached the right degree of maturity. The cuttings should be of current season's growth. The length of cuttings should not be more than 3-inches but can be smaller according to the growth of respective species; cuttings may be a joint or a heel as long as the cutting taken does not exceed 3 inches. With joint cuttings it is a good tip to split them about ¼ inch at the base across the bud. This helps to form a good callus.

The cuttings are inserted into a mixture of 2-parts sharp sand and 1-part Irish peat moss. Pans or cutting trays may be used, with coarse chippings for drainage. After filling the tray with the cutting mixture, ¼ in. layer of sand is put

In common with many other growers, we have experienced great difficulty in obtaining a crop of these plants from buds. I can claim nothing original in the method now adopted which over the last few years has given us excellent crops. It is based on a study of successful growers' methods and of the growth pattern of the Acer species in question.

Our first requirement is a young rootstock with a fibrous root system. A two-year transplanted seedling, 8 – 10 mm size seems ideal; anything larger is usually coarse-barked at the level of bud insertion. These rootstocks should be cut back to 18 inches and planted in well-manured ground; it is essential that the stock grow vigorously throughout the

There was no advantage in re-inserting cuttings after the initial lifting, as very few additional cuttings rooted, whilst the remainder quickly degraded. The new plantlets were then potted into four-inch clay pots in a pure peatmoss

Early in 1968 it was decided that we should try Acer palmatum ‘Atropurpureum’ from cuttings. Thirty-three stock plants were therefore taken under glass in February, bedded in a frame filled with peat and given regular doses of liquid feed throughout the growing season. The temperature was kept at a minimum of 45°F and, at the beginning of April, the first batch of cuttings were taken when the shoots were long enough and one pair of leaves had fully expanded. Cuttings were then taken at intervals

Various reports, such as those of the I.P.P.S., and the Woody Plant Seed Manual (published by the Forestry Service of the U. S. Department of Agriculture) have been found particularly useful. This latter book is notable for its detailed work on the treatment of seeds with sulphuric acid. A visit a few years ago to the Forestry Commission Nursery at West Moors, near Ringwood in Hampshire, also provided us with ideas on different seed-raising techniques. These changed practices have increased the quality of the seedlings we have raised and reduced our production costs.

The present business of F. Toynbee, Ltd., comprises a wide and complex pattern of wholesale trade despatch, contract supply, landscaping and retail sales. The choice of plants grown here is partly determined by the advice of the propagator.

The management must decide wheather to grow an increasing number of different kinds of plants or reduce to a few hundred which have a guaranteed minimal annual sale. Whichever choice is made, an estimate of plant quantities is required, close to actual sales, and an

Raising plants from seed is of considerable importance to the propagator of alpine plants who must be prepared to meet a range of spcialised requirements. Primula whitei, P. edgeworthii and P. gracilipes and their relatives of the Petiolaris section produce seeds which rapidly lose their viability. They must be sown as soon as they are ripe, with the seeds taken directly from capsule to seed-pan. Some people, however, have been led to the mistaken conclusion that all species of Primula should be so treated. In fact, the greater number of species respond far better to a spring-sowing programme; in this way they grow and develop and are ready to enter the normal resting period when winter arrives.

The seeds of Gentiana verna and Lewisia

Preparation for the grafting of miniature rose trees starts at the beginning of November. The second-grade miniature rose trees are pruned fairly hard, potted up into four-inch ‘long toms’ and placed into a cold frame or glasshouse where they are given a cold period for about four weeks.

The grafting pit is prepared in early December with about 9 inches of peat. We like to get the peat at a temperature of 80°F, with an air temperature of 72°F. The peat is watered to keep the inside of the grafting pit humid, care being taken to ensure that the peat is not so wet that excess water can be squeezed out by pressure. Air and soil thermometers should be placed in a convenient position in the pit in order to keep a regular check on temperature. Two Dutch lights, one on top of the other, are placed the length of the grafting pit in order that the condensation particles which form on the glass are smaller thus preventing too much water from falling on the grafts. In mid-December the

1. Mr. Neil Treseder had started research on a comprehensive book on "Temperate Magnolias and Their Hybrids", and had commissioned an artist to paint a set of the best forms to use as illustrations.
2. We knew that a few grafted plants of selected clones of Asiatic magnolias existed, and that these had reached flowering maturity considerably sooner than seedling plants of the same type (e.g. Magnolia campbellii subsp. mollicomata convar. williamsiana ‘Lanarth’.
3. Mr. Treseder anticipated that the coloured illustrations in his book would stimulate a world-wide demand for plants of selected clones.
4. Early in 1967 Mr. Treseder carried out investigations into the propagation of magnolias by bud-grafting, including methods used in America and Japan. He learned that Japanese nurserymen were achieving considerable success by direct budding onto two-year M. kobus seedlings in open field conditions whilst still in

In designing this house a number of problems had to be solved. These were:

1. Control of humidity
2. Efficient heating
3. Control of air temperature
4. High light with minimum heat
5. Low maintenance cost

First, atmospheric humidity is electronically controlled by use of an Hygrodynamics, Inc. humistat. This humistat is extremely sensitive in the range of 70% to 97% humidity while being almost maintenance free. This humistat is tied into the hydraulic and pneumatic mist systems by relays and solenoids and operates either, or both, as needed. The hydraulic system is under the bench and is capable of maintaining a humidity of 80%, when used by itself. The nozzles are Flora Mist and spaced 4 by 8 with an operating pressure of 90 pounds. This system uses 75,000 gallons of domestic water per day

Why use bins?

1. To increase the number of field liners over that which can be obtained from using more traditional methods such as hardwood cuttings in the open or in cold frames, e.g. Cotoneaster × watereri.
2. To propagate ornamental plants closely related to fruit tree rootstocks, e.g. Prunus cerasifera ‘Nigra’, Malus ‘Profusion’.
3. To propagate ornamental plants not normally propagated by hardwood cuttings, e.g. Crataegus ‘Paul's Scarlet’, for use as a hedging plant. By simplifying, the cost of production can be reduced.

Siting. Ideally the bins should be placed on the north side of

There are two methods of producing a plant in a container:—

1. Container-grown. Plants are grown in containers throughout their life.
2. Field-grown then containerised. One-year liners or older plants are lifted from the field and potted into containers.

In order to achieve our objectives we use the "container-grown" method to produce all our plants, with the exception of trees and roses which, because of their method of propagation, do not fit easily into this system.

We chose this system for the following reasons:

1. We have more control over plant growth, which in turn leads to a more uniform product.
2. The

We operate our nursery as three small units. The smallest, operated by my father and two women part-time workers, produces from seed as many plants as possible in boxes of 60, for transplanting on to spare beds in the nursery. As we use farmyard manure regularly we find this good preparation for rotation of shrub planting.

The second unit

Cutting material used in England is quite different from ours. In Boskoop we usually take weak-growing side tips of young plants in full growth. It must be remembered that in Boskoop we have to send you small plants because of import taxes, transport costs, etc; so we have to take our cuttings from young plants, whilst you, perhaps, may take them from larger plants which we do not have.

Conifer cuttings are taken during autumn which, as I shall subsequently show you, is usually the best time. So far as I know the selection of the right time is largely by trial and error and with the art of "green fingers". The Adivsory Service takes it for granted

1. Rooting of cuttings. This can be subdivided into —
1. treatment of the stock plant;
2. application to the cutting in the actual rooting bench.
2. Establishment of rooted cuttings. This can be interpreted as the continuation of growth to delay or prevent dormancy, with the aim of reducing losses of specific deciduous subjects during the winter.
3. Breeding. To speed up a breeding programme when plant breeders are anxious to see the results of their crosses earlier, e.g. Rhododendron, which has flowered after 3 years, instead of 6 years. It may be practical with some subjects to cause plants of early and late varieties to bloom simultaneously so that they can be hybridized.

I have purposely used the term "lighting" in this paper, as supplementary

The party visited the Research Station at Boskoop where they were greeted by the new Director, Dr. Roelofsen, himself an I.P.P.S. member. After an excellent ‘koffietafel’ at the Hotel Florida, four nurseries were visited —
          Fa Th. Streng and Fa J. Streng (2 nurseries)
          Fa G. Kooy and Zn.
          Fa F. J. Grootendorst and Zn.

I feel that in order to upgrade the industry, basic research from institutions all over the world must be translated into applied research within the institutions and within the industry. A free exchange of information in detail amongst teacher and students, research scientists, and members of the industry is very important. A seemingly insignificant detail found in research may prove to be the missing link which may bring success to a practical plantsman. Or close daily observation in the field can bring to light valuable insights to be pursued further by the scientist or student.

The industry needs to cut down the lapse of time between research and practical application in the nursery. Organizations such as our International Plant

These problems may be overcome by using small units or pots filled with a propagating medium in which cuttings can be rooted, grown, or shipped without removal from the rooting medium. This process saves labor the cuttings may grow better than those removed from the rooting medium because chances for root desiccation, breakage, and infection are reduced. Several individual, direct-rooting media have been developed for use with

We are using continuous mist for summer propagation of ornamental broadleaf evergreen and deciduous stock. We also propagate some fruit rootstocks by softwood cuttings under continuous mist: Prunus besseyi, P. tomentosa and some other plum rootstocks. One must be selective as there are a few species that do not tolerate continuous mist. Since our mother stock block is near our lathhouse, we moved our propagating benches right into the lathhouse to avoid drifting mist and to provide some shade from the hot sun. The benches are 30 inches off the ground, four feet wide with eight inch sides. The water is brought in through a one-inch line that runs along the base of the bench's front side with a ¾ inch outlet every four feet. This gives every four square feet of bench space an

When plants are grown from seeds, characteristics which appear on the young seedlings often differ greatly from those which are found later in the plant's life. In the case of pines, the first or juvenile shoots are gradually replaced by mature growth. This slide showing seedlings of Pinus canariensis illustrates the transition from the juvenile to the mature stage. The presence of juvenility at the lower portions of the plants is indicated by pliable stems bearing solitary leaves which are bluish-green in color and are of soft texture. Evidence of maturity is manifested in the upper portions by leaves that are borne in bundles of three, are grassy-green and of firm texture. The interval between the advent of maturity and time of

The past 15 or 18 years have produced many variations of the use of mist propagation systems. Many of you here have heard a number of them described and no doubt have used one or more of them. We, at Bailey's, are very happy with a circular bed. My nephew, Rodney Bailey, discussed this with you two years ago. We are even more sold on the system now.

All of us are familiar with the fine stands obtained with many varieties when greenhouses are used. You are all familiar with the cost of building a greenhouse as well as the rather high maintenance cost. We need a reason for considering going to any other method. The reason we at Bailey's have adopted the outdoor method is purely a matter of economics. We are producing a

The method currently being used by The Rhode Island Nurseries was developed and perfected by a valued friend of mine: my predecessor and the Dean of American Propagators, Mr. Martin Van Hof. Previous references to this subject can be found in papers by Mr. Roger Coggeshall in the 1953 edition of the Proceedings and by Mr. A. R. Buckley in the 1955 edition of the Proceedings. Mr. Van Hof began his experimentation with this method in the early 1950's and it has been perfected over the years. In my brief association with The Rhode Island Nurseries I have found this method to be extremely simple and at the same time highly

I once visited a large nursery in Germany. It was said to have several thousand glass-sashes in its propagation area. The amount of people needed to take care of this and carry sashes around ran almost into the hundreds.

Some years ago my close associate, John Wilde, and I started out with the goal of developing a practical system for propagation in outdoor frames. Our three main premises were: (1) it had to be well adapted to the ornamentals we desired to grow; (2) it had to be economical; and (3) it had to be suited for large scale production. Through modification of methods used by other propagators and some new developments of our own we have come a long way toward this goal.

To paint the clearest picture for you, I have divided my subject into three subgroups:

1. Frame Construction
2. Propagation in the Frame
3. Adaptability

Frame

What is the nature of growth of woody plants in temperate regions? Woody plants break buds and initiate growth from preformed parts in the spring. This may constitute the total height growth for the season in some plants; however, in other plants it may not. The growth of woody plants can be divided into two basic patterns. The first of these patterns can be referred to as homophyllous which

Growth regulating chemicals also have been suggested as a means of increasing flowering of rhododendrons by Cathey and Taylor (1), Criley and Mastalerz (2), Crossley (3) and Ticknor (7) and Ticknor and Nance (8). Most of this work was done under greenhouse, conditions, although the variety ‘Roseum Elegans’ growing in the field was used in some previous trials.

To test the relative merits of these two systems of increasing flowering of field-grown rhododendrons under Willamette Valley conditions, a trial was started in 1968. Five varieties— ‘Elizabeth Hobbie’, ‘Princess Juliana’, ‘Pink Pearl’, ‘Roseum Elegans" and ‘White Pearl’—known to vary in ease of budding were planted June 19, 1968. One month prior to

We have often said, and I know many of you folks have too, if we could only stop this growth the latter part of August or early September and be satisfied, instead of pushing our plants right up until the last good fall day. One method, which is time proven, of course, is to dig every plant around the middle of August and check its growth, but that went out with the depression when labor wages started skyrocketing.

Clonal propagation of some plum rootstocks by hardwood cuttings is more economical and less time consuming under English conditions than the conventional stooling and layering techniques (2, 4, 7). Garner (7) rooted plum rootstocks by collecting hardwood cuttings in the fall and storing them in insulated bins for the winter months at a basal temperature of 45°F. The cuttings were budded in the first growing season and produced satisfactory trees.

In Ontario, imported Myrobalan plum seedlings have been widely used as plum rootstocks. They were quite variable in vigor and there was no assurance that they were virus-free. Interest in propagating plum rootstocks in Canada has been increased by a recent embargo on the importation of nursery stock from Europe. The present investigation was undertaken to study the feasibility of clonal propagation of different plum and peach rootstocks under Ontario conditions.

Decreasing damage caused by fungi and other microorganisms is among the principal means of improving methods of propagating woody plants by cuttings. Softwood cuttings under mist or in propagation boxes provide particularly favorable conditions for the growth and spread of fungus diseases. To produce important economic benefits, a fungicidal treatment should meet three conditions: (1) the treatment must appreciably reduce the incidence of disease; (2) the treatment must not be harmful to the plant material being propagated; and (3) the treatment must not interfere with the rooting/establishment process.

Under intermittent mist, cuttings of many species of Prunus are susceptible to Botrytis cinerea and a number of other pathogens. Selection and utilization of asexually propagated rootstocks for peach, plum, apricot and sweet and sour cherries depends in part on development of disease control systems.

Three types of damage by fungi may be distinguished on many lots of Prunus

I think that misting has helped in solving some of these problems. It eliminates dehydration and drying-out of plants. With misting you don't have to be "Johnny on the Spot" with watering. There has been a great deal of loss without humidity control. We have experienced this over a number of years in precooling azaleas. It was all due to lack of knowledge of misting in cold storage.

Our first experience with misting came a few years ago when we had to rent cooler space and there were humidifiers in them. We were using the coolers for summer chilling, giving the azaleas six weeks of cold storage to produce late September and early October bloom. After the plants were in these coolers for six weeks, we could tell the difference in forcing. They came out with more lush foliage and seemed to react better to forcing. Also, we didn't

I'm sure most of you know what a witches' broom is, but for the benefit of those who are in the dark, I'll first try to describe what witches' brooms are and why they hold such fascination to those of us who are collecting and experimenting with them.

A witches' broom is an abnormal shrub-like growth that occurs only occasionally on various species of woody plants. Most often, it occupies only a small part of the tree while the remainder consists of normal leaves and branches. The broom is considered abnormal because its structure usually differs quite sharply from that of the normal part of the tree. The development of the broom is not the result of a gradual change in structure, but is abrupt, and its point of origin is easily identified (Fig. 1).

I prefer to categorize brooms into two groups; 1) those that are caused by parasitic agents, such as dwarf mistletoe,

This small tree has great popular appeal and many people are anxious to acquire it. However, owing to propagational difficulties, it has remained rare through the years and demand has exceeded supply.

Acer griseum was introduced

Our firm began as a market garden operation owned by the late Mr. Frank Reeves. Starting on the recently vacated premises in 1923 the business evolved from a position of solely growing vegetables to include a floriculture crop of chrysanthemums, snapdragons, etc. After Ken Reeves returned from the European theatre after World War II, he worked for a couple of years with his uncle, the late Cecil Delworth. Doubtless the experience he gained during his time with ‘Uncle Cec’ had a definite effect upon the future course

Most growers have now overcome the problem of overwiner storage by use of Quonset poly-houses. These houses are constructed over the plants in the growing areas, eliminating or reducing labor costs for moving plants. To make use of the short growing season, growers have also met the challenge by developing an efficient growing program. This parallels the year-round problems of the commercial florist. His problems are very much like those of the container grower. He is limited to growing his crops

At the Bosley Nursery we have been propagating a similar line of plant material under mist with the same water source for a number of years. We have never had as high a rooting percentage as others in this Society profess to achieve but then we didn't always tend to believe some of the figures we heard. In the 1968 summer and fall propagation season our results were even worse and it prompted us to have the mist water checked for agricultural suitability. We found the total soluble salt content to be moderately high for mist propagation of azaleas and rhododendrons. What was even more damaging was that the concentrations of both sodium and chloride were high for these sensitive crops.

The choice became: 1) find a new source of a better quality water; 2) install de-mineralizing equipment; or 3) stop growing those crops. We chose to install city water which is of much

Even though the art of graftage has been known and used in plant propagation for centuries relatively little is known about stock-scion relationships. There has been quite a bit of work done to study the influence of rootstock on plant growth and some on nutrition but very little work has been done to study the influence of rootstock-scion interactions as they might affect hardiness.

The rootstock could affect scion hardiness in one of several ways. Hardy rootstocks might induce hardier scions strictly through their use. The root system of certain rootstocks may have the ability to survive or escape root injury where other rootstocks cannot. In studies at Minnesota we have found that there is quite a range in hardiness capabilities of the various Malling and Malling-Merton stocks. Other workers have reported similar results (1, 2). Certain rootstocks may, due to earlier maturity or later bud-break, enable a scion variety to escape early and late winter injury by hardening

The plant species currently receiving most attention in the breeding program belong to the genera Ilex and Cornus. The starting point of the breeding project with each species has been the initiation and maintenance of a cultivar performance trials. Such trials are important as they make it possible to evaluate plants of the currently available cultivars under reasonably uniform conditions at one planting site and, thus, to assess the variability present within the cultivated plants

The distinctive clone now offered as ‘Griffin’ is believed to be the result of chance hybridization. It is probably a later-generation hybrid, which appears to be fully fertile, unlike the known F₁. hybrids between diploid M. virginiana and hexaploid M. grandiflora, which are often highly sterile.

The original ‘Griffin’ plant, in a city park at Griffin, Georgia, is a multistemmed, compact

1. Magnolia ‘Ballerina’ is a Loebner magnolia, seedling of M. × loebneri ‘Spring Snow’, possibly crossed with M. stellata ‘Waterlily’. Of similar season to the well-known Loebner magnolia ‘Merrill’, this has considerably more double flowers (to 30 + petals), is slightly pink-blushed and more highly fragrant. Judged by its first twelve years growth, it apparently will mature as a smaller tree than ‘Merrill’, but larger than M. stellata. The 1969 tests showed a high percentage of strong rooting with May

MODERATOR SHUGERT: Good evening, Ladies and Gentlemen; we shall now call the Question Box Session to order. For the benefit of those attending this session for the first time we ask all to participate. In order to have proper identity, we are asking everyone to do two things; wait for the microphone, and please give your name so it can be entered in the Proceedings. This can be very enlightening and interesting segment of the program if everyone will cooperate and participate. Thank you.

Now for the first question. Dr. Tehrani, how does your method of rooting hardwood cuttings work for ornamental varieties of cherries and flowering crabs?

G. TEHRANI: It does not seem to work too well with varieties of cherries; and I do not work with apples, so I have not tried this.

JOERG LEISS: The same type of treatment as Dr. Tehrani mentioned has been used on the Malus understocks of the

Later I decided to try it on some evergreen cuttings we were making. The ones we used were the following: Thuja occidentalis ‘Nigra’ T. O. ‘Fastigiata’ (syn., ‘Pyramidalis’) Juniperus horizontalis ‘Plumosa Compacta’, J. chinensis ‘Hetzii’, Taxus × media ‘Hicks’, T. × m. ‘Hatfield’, T. ‘Densiformis’ and Buxus ‘Newport Blue’.

In preparing the bench, I white-washed it then laid polyethylene on the bottom of the bench and put in 6 inches of washed cement sand. The bench was then leveled off with a 2 × 4, much as you would do to float-off cement. I don't do any pounding of the sand to firm it; I just stick the cuttings into it. The cuttings

Objective of this study was to determine the relationship between rooting cofactor or inhibitor level and the clonal and seasonal variation in rooting response of cuttings in three clones of rhododendron.

Past attempts to find such a test have generally failed. Symptoms such as chlorosis, leaf drop, initiation of cambial activity, initiation of first-year bud elongation, amount of scion and stock

Even if only 25 5's per month are lost to disease, and this can be prevented, money would be saved. Another point in favor of good sanitation practices is the fact that chemical control over disease, once the disease is