The Magic of Growing Plants: Dahlias, Avocados, and the Possibilities of Horticulture

Originally published in five surviving weekly installments in the Eagle Rock Advertiser, November 28–December 26, 1930

By J. J. Broomall

Original text by J. J. Broomall is in the public domain. Compilation, editorial notes, introduction, biography, and revised text copyright © 2026 by Steve K. Lloyd. All rights reserved.

In the surviving installments of The Magic of Growing Plants, J. J. Broomall begins with the flower he knew best and then deliberately moves beyond it. The series opens as a broad statement of his interest in plant improvement, with the dahlia serving as his principal example. He reviews variation, cultivation, breeding, heredity, and the transformation of the dahlia from comparatively simple forms into the cultivated flowers of his own day.

By the third installment, however, Broomall announces a change of direction. Under the heading “Mission of the Dahlia,” he argues that the flower’s greater importance lies in what it can teach people about the improvement of plants generally, “economic as well as ornamental.” He then leaves dahlia culture “for the present” and turns first to the avocado and then to the cherimoya. This broadening is Broomall’s own, not an editorial rearrangement.

The result is an unusually revealing late statement of Broomall’s horticultural outlook. Plant breeding, food production, experimentation, cultivation, and human welfare all become parts of the same project. His predictions and scientific explanations are presented here as historical claims rather than modern conclusions.

Only five installments are presently known. The fifth, published December 26, 1930, ends with “CONTINUED NEXT WEEK.” The issues of January 2 and January 9, 1931 are unavailable, and the surviving series therefore has no recoverable ending.

Installment One — November 28, 1930

In the notes on plant life which follow I have no desire to pose as a “knowall.” The fact is that after many years in the study and cultivation of plants I am just beginning to realize how ignorant I am. I have just awakened to the wonderful and unlimited possibilities of plant life and the limitlessness of the amount of knowledge that awaits the student of plants in his efforts to improve them.

The little I have learned of plant improvement has enthused me, and knowing as I do the importance of a better understanding of it by the public, I feel that I should be delinquent in my duty to human beings if I failed to do what I can to cause others to take a greater interest in plant culture.

I wonder how many people ever stop to think that our very existence depends upon plants. Plants are the connecting links between ourselves and Mother Earth. Nearly every ounce of solid material in our bodies must come to us from the vegetation that extracts our nourishment from the earth, which in [illegible] one sense we live.

The subject of plant improvement is so vast that I can touch only a few of the [illegible] that I have learned about. If what I shall say may cause others to become interested in the most vital and essential science of all, I will feel that I have not written in vain.

I will first try to explain how the dahlia has been improved, for the reason that I have had more experience in growing it than perhaps any other plant, and for the additional reason that many are anxious to know how its marvelous improvement has been accomplished.

Apropos to this I want to say there is no such thing as a “plant wizard.” There is nothing supernatural or very mysterious about producing new and improved forms of plant life, but an unlimited amount of work and intensive study, coupled with an ambition to accomplish something worthwhile, is absolutely necessary to insure success.

The one thing that makes possible the improvement of nearly all plants we cultivate is PLANT VARIATION.

No two plants are exactly alike. In the wild state the difference may be so slight as to pass unnoticed, but when plants are brought under cultivation the change in environment, and particularly the character and amount of plant food it receives, is certain to produce marked changes in the plant.

If the plant should happen to be what is known as a “gross feeder,” that is, one that is capable of drawing its nourishment from the earth very rapidly, the change will be much more noticeable.

The dahlia is a gross feeder. In its wild state it had to struggle for its existence, generally in competition with other plants, on a limited amount of nourishment that varied but little in character. When it was brought under cultivation and given an unlimited amount of available food very different in chemical content from what it had been accustomed to, it is not surprising that it should do something different. Indeed, a change in the plant’s action was inevitable.

In the cultivation of any plant it is a great advantage to know something of the climatic conditions where such plant is indigenous. The species of the dahlia from which those we now cultivate have been developed are natives of Southern Mexico. Now do not get the idea that the dahlia is a tropical plant, for it is not. Southern Mexico has a wide variety of climates a comparatively short distance apart. Near the coast is the Sierra Caliente (hot region), and still further inland, at an elevation of six thousand feet or over, is the Sierra Fria, or cold region, (literally translated “cold earth”) with a climate that can scarcely be surpassed. It is upon the rocky slopes of the mountains in this region that the dahlia grows in great profusion.

These wild dahlias, however, are so different in appearance from those we see nowadays that many people would not recognize them as being dahlias.

The dahlia dislikes intense heat and cannot be expected to produce perfect flowers when the thermometer registers higher than 90 degrees in the shade, yet it will adapt itself to a wide variety of climates and environment. They are grown successfully in the Philippines and in Hawaii at an elevation of 4000 feet or over, and equally as fine blooms have been produced at Skagway, Alaska, close to sea level.

Installment Two — December 5, 1930

I shall say but little about the earlier history of the dahlia. Much of what I have read on the subject is rather vague and more or less contradictory, but to those who would like to learn more about its earliest culture by Europeans I recommend The Amateur’s Book of the Dahlia, by Mrs. Charles H. Stout (published by Doubleday, Page & Co., New York), as it is by far the best book that I have read on the subject.

Dahlia variabilis, from which the common old-fashioned dahlia is supposed to have originated, was single in its wild state, generally having but eight petals surrounding the central disk. The name variabilis was given because seedlings raised from it varied greatly in color without hybridizing. The first perfectly double flowers were obtained by M. Dankelaar of the Botanic Gardens of Belgium in 1814, and this was the forerunner of the common double dahlias so common in the gardens of the East more than half a century ago.

This doubleness was undoubtedly caused by a superabundance of plant food and the best possible cultivation of the soil.

In 1872 a new type of dahlia was discovered in Mexico. History fails to state whether it was found growing wild or in the garden of some flower-loving Mexican. This dahlia was given the specific name of Juarezii in honor of a former president of Mexico.

Ten years later it was shown in London by Henry Cannell & Sons, when it attracted a great deal of attention among English florists. The name “Cactus Dahlia” was given it because the blossoms resembled the flowers of the cactus Cereus speciosissimus in color, it being a very attractive shade of red.

Dahlia Juarezii, though comparatively small and inconspicuous as compared with some of its gorgeous descendants, was destined to revolutionize the growing and production of new varieties of dahlias, for it not only “broke” into different colors but into a variety of shapes as well, some of its progeny bearing flowers with longer petals, the edges of which were rolled back so that they were much more narrow and pointed than those of the parent flowers. By selecting the most desirable of these seedlings from each succeeding generation, English growers led by Henry Cannell, who might well be termed the “godfather” of the Cactus Dahlia, succeeded in producing some of the most beautiful garden flowers the world has seen, so different in appearance from the old-fashioned dahlias we had been accustomed to that it was hard to believe that they really were dahlias.

Unfortunately many of these new creations of expert English growers must be described as “good for exhibition only,” as with a few exceptions the plants were deficient in vitality. The stems were weak and very few of them were at all suitable for cut flowers.

The cause of this weakness was the continuous selection too close to type or to the desired shapes year after year without any mixture of new blood. For excessive inbreeding is as certain to result in weakness of the succeeding generation in plants as it is in animals.

Not until the latter part of the 19th century do American growers appear to have given much attention to the culture of the cactus dahlia, but when they did it was not long before things began to happen. The so-called hybrid cactus and decoratives began to appear. These were the result of crosses between the old-fashioned dahlias (show dahlias as they were known to the trade) and the finer English-bred cactus dahlias, and these crosses were the forerunners of the magnificent creations to be seen in the garden and exhibition halls at the present time.

The crossing of the species and later on of the varieties not only resulted in many new types and tints but also flowers of immense size held erect on strong stems supported by plants of extraordinary vigor. For as inbreeding results in weakly plants, so does the crossing of widely differing varieties tend to produce plants of greater vigor and flowers of larger size.

Installment Three — December 12, 1930

I have found in my experiments that almost invariably the greater the difference between the parents the more vigorous would be the offspring. But readers should not get the idea that ALL the flowers obtained by crossing are an improvement upon either one or both of the parents, there is always a tendency towards retrogression. The fact is that only a very small per cent will be an improvement and worth saving from a professional point of view. If a grower succeeds in getting one in a thousand that is a distinct improvement over pre-existent varieties of similar color, he may consider himself fortunate.

People are apt to gasp in astonishment when they are told that the price of a new dahlia is $25 or $50 per plant, but how many realize the plant in question may be the best in a lot of ten thousand seedlings, and that the other thousands, which finally go into the discard and can bring no remuneration to the grower whatever, must have received the same diligent care and scientific culture in order to determine their merits as the one or very few, sometimes not more than one in a thousand, that does prove to be different from or an improvement upon varieties already in cultivation. And this goes to prove that few things worthwhile in this life can be accomplished without intelligent effort and a lot of it.

In dahlia breeding, growers who depend upon hand-pollenizing and hybridizing alone are quite liable to be disappointed in the results, for most of the finest dahlias we now have are the results of probably thirty or forty years of crossing and recrossing, and the resultant seedlings are more apt to show some of the characteristics of their more remote ancestors than they are to resemble their more direct parents, for heredity plays an ever increasing part in the dahlia as well as in many other plants.

While heredity may upset one’s calculations in the breeding of plants it may also be of the greatest assistance to the grower, for I have found out by experience that some dahlias are much better parents than others. Some of the leading varieties are unsatisfactory as parents, the percentage of desirable seedlings being so small that it does not pay to bother with them, while some that may not be so fine produce a much larger number of fine varieties.

The best for the purpose can only be determined by experimenting. The superior merits of such parents for breeding is proof positive that their ancestry must have been better, and it is also proof that “blood will tell.”

The most important thing of all in the improvement, not only of the dahlia but of every plant that has been or is being bred into things of greater beauty and usefulness by the industry of man in cooperation with the forces of nature, is good cultivation, for without that any worthwhile improvement would be impossible. And this good cultivation that is absolutely necessary means any amount of intelligent effort and an unlimited amount of labor.

Before saying anything further in regard to the improvement and culture of the dahlia I have in mind something of vastly greater importance, which I will preface by what seems to me to be the mission of the dahlia.

While the improved varieties of the dahlia, including as they do some of the most gorgeous flowers the world has yet seen that have added to the pleasure of millions and to the joys of living they have performed a service of much greater benefit to humanity than the mere enjoyment of the beautiful by awakening many including the writer to the wonderful and unlimited possibilities of improvement in many other plants economic as well as ornamental. The growing of ornamental plants is all right. It differentiates us from the “cave man.” Nevertheless, even in this highly civilized age it is very essential to have something to eat, and the better we understand plants the better we shall fare.

For this reason I will say no more about dahlia culture for the present but will try to present to readers some facts concerning certain food-producing plants.

The greatest of all food-producing trees, so far as known, is the Avocado, botanically known as “Perseas Americana”. I believe the fruit of this tree is destined to revolutionize food production in California, a fruit so nutritious and healthful that eventually more of it will be used than any other article of food, with the possible exception of bread. Moreover, the time is not far distant when the value of this fruit crop will be far in excess of the value of the citrus crop because the fruit I am going to describe is a real strength producing, health giving food and in no sense a mere luxury. In my next installment I shall tell you more about this wonderful food producing tree, and I believe I can convince you of its supreme value and unlimited possibilities.

That some of the most noted horticulturists in America have equally as good an opinion of the avocado, I quote the following from Manual of Tropical and Subtropical Fruits by Wilson Popence, with whom I became acquainted more than 20 years ago, and permit me to say that this book should be in every library in Southern California.

Of the avocado Mr. Popenoe says in part: “Four or five tortillas (corn cakes), an avocado and a cup of coffee is a good meal,” say the Indians of Guatemala. “It is precisely this condition, the importance of the avocado as a food in those parts of tropical America where it has been grown since immemorial times, t hat has led students of this fruit in the United States to predict that avocado culture will some day become more important than citrus culture in California and Florida.”

“To a certain extent the avocado takes the place of meat in the dietrry of Central Americans. It is appetizing, it is nourishing, it is cheap and it is available throughout most of the year. When these last two conditions have been reproduced in the United States, will not the avocado become a staple article of diet with millions of people?”

Installment Four — December 19, 1930

There is every reason to believe that eventually the avocado will become as familiar to American housewives as the banana is today. The increasing scarcity of meat, and the fact that an acre of land will yield a larger amount of food when planted to avocados than it will in any other tree crop known at present, assures the future importance of the avocado industry in this country.

There are people who say they do not like the avocado, and there are others who say they are too expensive. This latter objection will soon be a thing of the past, for the time is coming, not very far in the future, when in addition to its other superior merits it is going to be the cheapest food on the market. I believe avocado growers are liable to have hard sledding for a while because the supply is almost certain to increase faster than the demand, but the growers can remedy this to some extent by educating the people in regard to their use, and there is no doubt in my mind as to the final outcome. If avocado growers are wise they will start a campaign of education at once.

It required a year for me to acquire a taste for the avocado. When I first tried to eat them they were nauseous to me, then someone told me to try a little salt, pepper and lemon juice on them and I found they tasted rather good. It was not long before I ceased to bother with the lemon juice and now I will not eat breakfast without them if I can avoid it. When I happen to be without them I have two or three eggs, but eggs are a mighty poor substitute for the wholesome, nutritious, satisfying and healthful avocado. After eating a breakfast of two or three slices of toast and a few ounces of avocado, I, at the age of more than three score and twelve years, am able to do four or five hours of manual labor without faintness or fatigue.

But the most wonderful thing about the avocado remains to be told, and that is the almost endless variety of them and the unlimited opportunity for their improvement. It is said that there are a thousand varieties of the avocado. I opine that this is more apt to be an underestimate of the number than otherwise. The ease with which they can be grown from seed is certain to result in many thousands of seedlings being grown. Many of these seedlings will produce fruits of inferior quality, but following the law of averages which holds good in the variation of all plants that are improved by hybridizing and selection, a few are certain to be an improvement in size or quality (sometimes both) over their progenitors, so we may look forward confidently to greatly improved varieties in the future.

Unlike some plants, the undesirable seedlings need not be a loss, for by improved methods of grafting and budding, buds of the very best varieties can be worked on what would otherwise be worthless trees, converting them into the very best varieties, and they will begin bearing within two years after being budded. Some of the budded trees are apt to be more vigorous in growth and more prolific bearers than those grown on their own roots because it very often happens that the seedlings are extra strong growers and the budded variety will have the advantage of a stronger root growth.

Another thing to be gained by experimenting with seedlings is that varieties will be obtained that will be more hardy, succeeding where more tender kinds would be ruined by frost, thus increasing the area where the avocado may be successfully grown. And what is said in the preceding paragraph will apply to many of tropical or subtropical origin.

In my opinion the avocado has a wonderful future before it in this state, and the grower who devotes his best efforts to its culture and betterment will eventually be well rewarded and will contribute to the welfare of his fellow men. The wise grower, in addition to selecting the best in quality, will pay the greatest attention to those that are best for shipping, for the time is not far distant when avocados will be shipped to the East in trainload lots that will arrive in perfect condition in refrigerator cars. The demand will be unlimited. For every car of oranges now sold, ten cars of avocados will be used because the avocado is a real food containing nearly double the amount of nourishment of lean meat and much more easily digested.

Installment Five — December 26, 1930

Among the varieties of avocados grown at present, the Fuerte has been considered the leader as to quality. Analysis shows that it contains 30 per cent fat and the flavor is excellent. The very best avocado I have eaten of more recent introduction is the Mayapan. This is a thick-skinned variety very much similar to the orange in shape and weighing a pound when grown. The Fuerte begins to ripen in November, but the Mayapan requires a much longer time to mature, its season of ripening being from May to August. I would advise everyone who can to plant a Mayapan. It is a very rapid grower and will begin bearing the second year after planting. I have one growing on my place, planted two years ago, that has about all the fruit on it now that such a young tree should bear.

The Mayapan is rather tender and should be planted in a protected location, preferably the south side of a building if possible.

I am experimenting with seedlings and the first one of my own raising bore four fruits this year. I was as proud of them as an old hen with a brood of young chickens.

However, the chances of obtaining a first-class kind from seed is very uncertain, and if your space is limited and you are in a hurry to obtain satisfactory results, I would advise buying the very best budded trees from a reliable nurseryman. You are not liable to regret the investment.

I will now try to tell about a fruit that deserves in full the above title. It is 21 years since Mr. Wilson Popenoe gave me a fruit of the cherimoya at the Pasadena Flower Show. I thought then that it was the most delicious thing I ever tasted, and I am still of the same opinion regarding it. To show that others have the same opinion I will quote the following from the book on tropical fruits by Mr. Popenoe:

“Deliciousness itself is the phrase Mark Twain used to characterize the cherimoya.”

Sir Clements Markham, in an even more flattering description: “The pineapple, the manposteen [sic], and the cherimoya,” says Dr. Seemann, “are considered the finest fruits in the world. I have tasted them in those localities in which they are supposed to attain their highest perfection—the pineapple in Guayaquil, the mangosteen in the Indian Archipeligo, and the cherimoya on the slopes of the Andes—and if I were called to act as a Paris I would without hesitation assign the apple to the cherimoya. Its taste indeed surpasses that of every other fruit, and Heenke was quite right when he called it the masterpiece of nature.”

The cherimoya (Annona cherimola) is a subtropical fruit, a native of the highlands of Ecuador and Peru. While rather sensitive to frost, it can be grown successfully in California where the lemon thrives. There are cherimoya trees growing in Eagle Rock Valley more than 20 years old that have apparently lived through the coldest winters, but they are all located on the higher part of the valley and it would not be advisable to plant them on low ground where the frost is more severe.

I believe there are two reasons why more of them have not been planted here. One reason is that comparatively few people know anything about them, and the other reason is that for the most part only seedlings were planted, and many of these bore fruits of inferior quality, and some none at all, which is rather discouraging.

I have a seedling bush (they are called low-spreading trees in the book, but most of those I have seen were more like bushes, branching near the ground and seldom more than 10 or 12 feet high). My seedling has been growing quite a number of years. It has never borne fruit, but for several years it has blossomed profusely. That it has failed to bear may be due to wrong treatment, however, so I shall continue to experiment with it.

Incidentally, some very fine seedlings have been produced in the north end of the valley. I have one budded variety planted about seven years ago. Last year it bore one fruit, this year it has three on it. There is room on the bush for many more. However, I have great hopes for the future.

One very important thing that will apply to nearly all fruit trees. They must not be allowed to suffer from lack of moisture, especially at blooming time and when the fruit is being formed.

My plan of watering such trees now is to use an old piece of hose and allow a very small stream to run slowly on the upper side of the tree for a day or two until the ground around it is thoroughly saturated, and then as soon after the surface has dried so that the ground can be cultivated, give it a good hoeing. This conserves the moisture and encourages root growth, and remember, the roots will run out as far as the tree is tall, sometimes farther, and this applies to all kinds of trees and most plants as well.

1. Surviving extent of the series. Five installments are presently known, published from November 28 through December 26, 1930. The December 26 installment ends “CONTINUED NEXT WEEK.” The January 2 and January 9, 1931 issues of the Eagle Rock Advertiser are presumed lost, while the January 16 issue begins the separate article Dahlia Classification. The surviving Magic of Growing Plants series therefore has an open right edge; no ending has been supplied editorially.

2. Newspaper editorial notices. The first two installments originally carried introductory notices written by the Eagle Rock Advertiser editor, describing Broomall as an “Eagle Rock dahlia wizard” and introducing the series to readers. Those notices are publication-state paratext rather than Broomall’s prose and have not been incorporated into the principal reading text.

3. “Mission of the Dahlia.” The heading in the third installment marks an explicit authorial transition. Broomall’s argument reuses and reframes the central doctrine of his earlier The Mission of the Dahlia: that the dahlia’s larger importance lies in awakening interest in the improvement of economically useful as well as ornamental plants. The section is not established as a textual revision of either complete 1923 or 1926 Mission state.

4. Historical scientific and economic claims. Statements concerning heredity, inbreeding, plant nutrition, the causes of doubleness and variation, avocado food value, future consumption, crop productivity, hardiness, and other scientific or economic matters are Broomall’s historical claims. They are preserved as part of the text and should not be read as independently verified modern conclusions.

5. Source spellings and anomalies. The word-level text remains frozen to the page-image-verified source layer. Unusual or apparently defective printed forms, including “Perseas Americana,” “Wilson Popence,” “dietrry,” “Archipeligo,” and “Heenke,” have not been silently modernized or conjecturally corrected in this assembly pass.