Growing Fine Dahlias: Broomall’s Practical Guide to Dahlia Culture

The texts gathered here were originally published in J. J. Broomall’s 1922 Dahlia Guide, pp. 3–8, beginning with “How to Grow Fine Dahlias.”

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. 

By 1922, the recurring practical sequence surrounding How to Grow Fine Dahlias had developed into a compact suite covering nearly every stage of ordinary dahlia culture: soil preparation and conservation, planting, irrigation, insect control, the use of green plants, winter storage, and the handling of dahlias as cut flowers. Earlier versions had presented much of this material more continuously, but by 1921 Broomall had begun separating it under distinct practical headings.

The 1922 Dahlia Guide preserves a particularly useful state of that sequence. Among its additions are an expanded discussion of suitable soils, further instructions for storing and dividing roots, “Green Plants vs. Tubers,” and the concluding practical treatment “The Dahlia as a Cut Flower.” The historical headings are Broomall’s own and are preserved here. Their presentation together on this page is editorial; they should not be understood as a single Broomall-authored work under the title How to Grow Fine Dahlias.

The text below follows the 1922 publication state. Punctuation and paragraphing have been lightly adjusted for readability, but Broomall’s spelling, terminology, capitalization, numerical wording, and characteristic voice have otherwise been retained.

In a conversation with one of the most successful Dahlia growers in America we found that we had both entered the business in the same manner; i. e., we first raised Dahlias because we liked the flower, and allow me to say that this is the most essential thing in the business of growing flowers, whether by the professional or amateur. Indeed, it is hard to conceive how any one could grow flowers successfully if they do not like them well enough to give them the best possible attention.

It is my earnest wish that you who read this may be successful, hence I will do my best to give you the benefit of my experience. Owing to varying conditions, it is impossible to lay down rules that will apply everywhere and at all times, and I have seen fine Dahlias produced under conditions entirely at variance with the methods I follow. Yet I believe what I shall say will be helpful to many who have not had so much experience in flower culture.

The question is often asked, “What kind of soil should Dahlias be planted in?” I answer, any kind of soil; any soil that will grow cabbage or potato will grow good Dahlias. It matters not half so much about the KIND of soil as the CONDITION in which it is kept.

In planting Dahlias the soil should be put into the best possible condition before planting. The saying, “A task well begun is half done,” will certainly apply with full force in this case.

About a week before planting time, if the ground is not already sufficiently moist, it should be thoroughly wet two feet deep. Light sandy soil will be fit to dig two or three days after wetting, but in heavy clay or adobe soils it will be necessary to wait longer, as such soils should never be dug or planted when they are wet enough to be sticky. If the lumps crumble easily when struck with the back of the spade, then it will do to dig.

As very few private growers have gardens extensive enough to plow, I shall not say much about plowing, except that I believe in plowing as deep as possible, and if I could get a sub-soiler, I would use it. In digging ground for dahlias, it is not sufficient to merely turn each spadeful upside down in its original position, as the soil is never well stirred or completely pulverized by so doing.

There should be a space of two feet between the dug and the undug ground. To do this it will be necessary to pile the earth up where you start to dig, and to avoid having the surface uneven when you finish, it is advisable to finish digging near where you began. For instance, should the plot to be dug be six or eight feet wide, dig one-half the width going one way and the other half as you return; then the extra soil will be available to fill in where you finish.

The ground should be dug at least 18 inches deep. To do this, a second spading should be made. As this may be in the subsoil it should not be placed entirely on top of the surface soil, but spread on the side of the embankment.

In the miniature pit thus created between the dug and the undug ground should be placed all the weeds, leaves, old dahlia stalks and every kind of litter available that will decay within a year’s time. Even fine brush may be used to advantages, especially in heavy soils, providing always that it is covered deep enough so that it will not interfere with planting.

Now I am well aware of the fact that it is much easier to burn trash, so called, than to make the best possible use of it, but remember this: When you burn anything that is available for plant food, you are robbing the soil; when you use it, you are building the soil.

By so doing you are not only improving your chances for sucess this year, but you are making your soil more fertile and more easily worked in the years to follow. I can see no reason why ground used for growing dahlias should not, with the addition of very little fertilizer, become more fertile, as long as it is used for this purpose.

This conservation of the soil’s fertility is of the most vital importance; too much attention cannot be given it. Natural or animal manures are becoming more scarce, while the demand is steadily increasing, with the result that we will have to rely more and more upon chemical fertilizers, some of which give excellent results. But unless the continued use of such fertilizer is supplemented by the addition of some humus-producing material, deterioration of the soil is certain to follow.

For this reason every garden should have a compost heap, where all material that is possible to be converted into plant food may be saved until it is convenient to make use of it. If sufficient pulverized earth is added as such material is piled up, it will not be unsanitary, as the earth acts as an absorbent and prevents fermentation and offensive odors.

Nasturtiums or other quick growing vines can be used to prevent the heap from becoming unsightly. I believe the system of salvage in the garden or on the farm should be as complete as in the Kansas City packing houses where, it is said, “Nothing is lost about the hog but the squeal,” and now that we have the phonograph, even that may be canned.

In Southern California, dry roots planted in February and March will begin blooming in May and be at their best in Midsummer. Green plants set out as late as July 15th will, if properly treated, give excellent results in the fall. In the North and East Dahlias may be planted from March 15th to June 1st, according to locality, or a little in advance of corn planting time.

If planted in a single row, plant them at least three feet apart. They may be planted a little closer for hedge effect, but not if large flowers are desired, for when they are planted too close they will rob each other, and it will be a question of the survival of the strongest, and not always of the fittest. If more than one row is wanted, the rows should be four feet apart.

There is another thing to which I think growers should pay more attention, and that is the grading of plants according to their height when planting. If in a single row, begin with the tall varieties at one end and gradually taper down to the more dwarf and weaker growers at the other. For example, if such dahlias as H. L. Brousson or Frederick Wenham are planted between such rank growers as Dr. Tevis or Stunner, the former will not produce a flower worth looking at.

Make the holes five or six inches deep, so that the upper side of the tuber will be four inches below the surface. Lay the tubers in a horizontal position with the eyes or sprouts, if any are showing, uppermost. Never stand them on end.

I know not why, but fully half of the inexperienced amateurs I have met have the idea that a dahlia tuber should stand up, and if let alone they will probably stand at least one-third of them wrong end up. The first thing an unsprouted dahlia tuber does after being planted is to throw out feeding rootlets from the end of the tuber farthest from the eye, and four inches deep provides the most favorable conditions for quick and healthy root action.

Now if a tuber should be four to five inches long and is stood on end, the lower end will be eight or nine inches deep in cold, unaerated soil, where quick root action is impossible; and if the tuber happens to be wrong end up, imagine the struggles of that delicate sprout being obliged to start out in life under such unfavorable conditions.

After the tubers have been properly planted, let them alone. Above all, do not attempt to drown them, for in heavy soil you might succeed.

Dahlias planted as above directed should not be watered until they are in bud for bloom. A plant uses moisture in proportion to the amount of foliage it develops, so that until the tops are well developed, there should be, under normal conditions, sufficient moisture in the soil to keep the plants in good growing conditions.

After the plants are up, they should be well sprayed with clear water at least once a week in order to keep the foliage clean and healthy and to prevent injurious insects attacking them. About every ten days the ground should be hoed deeply, except within six inches of the plants, where it should be very lightly stirred.

In a country where irrigation is necessary this, in connection with cultivation, is the most important thing of all. Conditions vary so greatly that it is impossible to say how often they should be watered; the time may vary from five or six days to as many weeks.

I have seen fine Dahlias produced in Southern California without any irrigation, and I have seen them suffering from lack of moisture where they were watered every day. The habit that some have of splattering water from the hose on everything, every day, is simply a waste of time and water. Ground so treated will have a hard glazed surface, so that the water cannot penetrate far enough to benefit the plants, and the greater part is quickly lost by evaporation.

I believe furrow irrigation to be the best for Dahlias. If the Dahlias are in a row, make a furrow on each side of the row and allow the water to trickle slowly through the furrows for 8 or 10 hours, or until the soil is thoroughly wet underneath. If single plants are to be watered, make a circular furrow 8 or 10 inches from the plant, and fill and refill this furrow until the ground is wet.

As soon after each irrigation as the ground is fit to work, it should be hoed and the surface soil well pulverized. The cultivation after irrigation is the most important thing of all; if this is neglected it would be better many times not to have irrigated at all.

Bone meal sown in the open furrow after irrigation will improve the size and color of the blossoms; a small handful is sufficient for a blooming plant. The fertilizer should be covered soon after being applied.

If the ground is in proper condition when the tubers are planted, no irrigation should be necessary until the Dahlias are up several inches high. Never water them before they are up—in the earlier stages of growth spare the water but don’t spare the hoe; after they commence to bloom, this rule should be reversed to some extent.

Don’t irrigate any more than is absolutely necessary until the plants are ready to bloom, but cultivate frequently and thoroughly. After they commence to bloom the ground should not be hoed deeply, and when in bloom they must not suffer for water.

In ordinary soil, if the watering is done right it will not be necessary to repeat the operation in less than ten days or two weeks’ time, even when the plants are in full bloom, unless they are planted near trees or shrubbery. In that case the roots from these will use the greater part of the plant food and moisture, and this, of course, will call for heavier fertilizing and more frequent watering.

Some people apparently do not realize that in a dry country a tree 20 feet high will send out roots for 40 feet from its base in search of moisture, and this ratio will apply to the action of many plants.

While there are some very good remedies for most of the insect enemies of the Dahlia, I shall, instead of naming them, mention two very effective preventives.

First. I raise chickens for the sole purpose of keeping down the various bugs and worms, with the result that for years I have not been bothered with cut worms, wire worms, root maggots, stalk borers, and many other destructive pests that have been annoying other growers.

Ten or twelve hens per acre is sufficient. True, they do some damage, and are sometimes exasperating, but the benefit generally far exceeds the damage. It is of the utmost importance that they should have the run of the gardens at the time the ground is being dug, or plowed, as that is when they do the maximum amount of good with the minimum amount of damage.

In small gardens, where chickens can not be allowed to run at large, buy, borrow, or hire an old hen with a brood of young chicks; tie the hen by the leg, and the little chicks will do very effective work, and very little damage.

My second preventive is “Overhead Watering,” notwithstanding the fact that I have always advocated the “furrow system” of irrigation and believe in it yet.

During the war when help was scarce I obtained some revolving sprinklers, and the result has been so satisfactory that I shall continue to use them. In addition to being a great saving in labor they are an absolute preventive of Red Spider, Mealy Bugs, and Aphis of all kinds.

Overhead watering also greatly lessens the damage from thrip, and has a tendency to drive larger insects to the ground where the chickens can get them. In addition to this, blight and mildew have not been so bad as before the use of the sprinklers.

The sprinklers I use wet the surface from 30 to 60 feet in diameter, varying according to the amount of pressure available. I allow them to stand from two to five hours in a place, and then move them to the edge of the wet space, so as to insure the wetting of all the ground.

This is a good substitute for several hours of gentle rain, and the nearer we can imitate nature in this particular the better, for a gentle shower does not pack the soil as do other methods of watering, but has a tendency to make the soil more mellow. Ground wet as above described, if it has been properly cultivated, will be saturated from one to two feet deep, and—watch those plants grow.

I have often been asked, “Does not spraying the plants while the sun is shining injure the plants?” Yes, in time of extreme heat when the thermometer is from 90 to 100 degrees in the shade, which in Southern California means 120 to 130 degrees in the sunshine, the flowers are injured; but at such times, both buds and blossoms are generally ruined anyhow if no spraying is done. In ordinary normal weather I have never noticed any damage worth mentioning from overhead watering at any time of day.

The greatest damage occurs with me late in the fall, when the stems of some varieties are apt to be weaker, and the flowers very large. The weight of the water that collects on the bloom will cause it to droop, and sometimes break the stem, or bend it so that it fails to straighten up afterwards; but the damage from this source is in my estimation far outweighed by the benefits of “overhead watering.”

I would advise those who use other means of irrigation to thoroughly spray the foliage at least once a week during hot dry weather.

You should not get the idea that Dahlias are hard to grow. I know of no plant that will more surely and more abundantly reward the intelligent efforts of the grower.

One of the chief characteristics of the Dahlia, at which I have never ceased to marvel, is the amazing quickness with which they will respond to good treatment. It is not necessary to be a professional gardener. I have known some very dear old ladies who knew very little about scientific gardening who succeeded in growing fine Dahlias.

If you love the flowers and are determined to succeed, there can be no doubt about your success. If there is a commercial grower who did not first grow the Dahlia for pleasure—for the love of it—I have yet to meet him or her.

Especially would I urge all who can to plant and tend to their Dahlias with their own hands. Don’t be afraid of soiling your hands. It will come off. Of course, you may raise a few blisters before you raise the Dahlias, but blisters are not fatal, while inactivity too often is.

By tending to the Dahlias yourself, you will not only be rewarded long before they are in bloom by a better appetite and improved health, but your enjoyment will be much greater when they do bloom.

The man or woman who has not watched a beautiful flower expand, that has been brought into being by their own efforts, and has not been enthused and enraptured as Nature unfolded her handiwork, has missed—is missing—one of the joys of living.

There is a great difference of opinion among growers as to which is the best to plant, tubers or green plants. Under ordinary favorable conditions I prefer green plants for several reasons.

In the first place green plants are much less liable to become diseased than roots. It is seldom necessary to thin out the stalks when green plants are used, and they will as a rule produce as good or better flowers, as well as better tubers, which are generally cleaner, more free from disease, and much easier to divide.

Henry Cannell, the God-Father of the Cactus Dahlia, advises the planting of green plants; C. G. Forsythe, who always captures first prize at the Pasadena Flower Show, raises his prize-winners from green plants, and my friend, Mr. Alex. Waldie, of Santa Paula, who also has a habit of winning first prizes, prefers green plants.

I believe one reason why amateurs often fail with green plants is that they do not plant them deep enough. If they are taken from 2½-inch pots they should be planted fully twice as deep as they were in the pots, or from four to five inches deep.

If a plant has been rooted between joints, it may grow and bloom and not make any tubers; for unless the plant is deep enough so that a joint will be at least three inches below the surface, no tubers will form. The germs of life are existent in every joint of the plant, and the same joint that would, if above ground, throw out branches and produce flowers, will, if deep enough below the surface, produce tubers.

It depends upon the conditions and environments as to what action those germs take. For this reason it is better to err on the side of deep planting than not to plant deep enough; for even if two joints should be covered and the lower joint be covered so deep as to render it blind, nothing will be lost, as the tubers formed on the joint above will make up for it.

Another reason why green plants sometimes fail to give satisfaction is because inferior plants are used. Green plants should be grown under moderate heat, and in Southern California they should be kept in a lath house for four or five weeks after being potted, to allow them to become established and thoroughly hardened before being set out in the open ground.

That many plants have been forced under excessive heat and sent out before they were fit to plant has been the cause of many failures; and that is undoubtedly the reason why so many growers are opposed to them.

The appearance of my gardens in the late summer and fall should be a good argument in favor of the use of green plants, for more than two-thirds of it is generally filled with green plants.

In the Northern and Eastern states, Dahlias should be cut close to the ground as soon as frost kills the foliage, and the clumps carefully dug and stored in a frost-proof cellar or basement.

I find it a good plan to place the clumps in boxes, and cover them with three or four inches of pulverized earth to prevent them from drying out too much.

In Southern California the chief thing to guard against is the dry atmosphere, which is apt to cause the roots to dry and shrivel so badly that all the vitality will be destroyed and the roots lost. In California and, with a few exceptions, the entire Pacific Coast west of the Sierra Nevada and Cascade mountains as far north as Seattle, by far the best way to preserve the roots is to leave them where they have grown, undisturbed, until near planting time in the spring, provided they are not in a heavy clay soil or low situation from which the surplus water can not easily be drained, as the standing of stagnant water on the soil is certain to cause decay.

After the tops are cut the rows should be slightly hilled up; this will improve the drainage and also protect the crown from severe frosts. The clump should not be divided until planting time, if it can be avoided, as the divided tubers will dry out much quicker than the undivided roots.

It is better for amateurs not to attempt to divide the clumps until after they start to sprout; and it should be understood that the eyes are located where the tuber joins the stalk and nowhere else. If you have had no experience better get some one who understands to show you how it should be done.

From a place of comparative obscurity a few years ago, the Dahlia has become one of the most popular flowers in the cut flower market. While this increase in popularity is due in great measure to the improved varieties, the fact that florists have found out how to treat them to increase their keeping qualities has also been an important factor in bringing about this important change.

It has been found that by burning or scalding the ends of the stems, thereby preventing the sap from escaping, they will last much longer. I have found scalding to be the most practical.

I do this by holding the ends of the stems in boiling hot water for three or four minutes, and immediately placing them in cold water fully three-fourths the length of the stems.

During the hot season I think it is best to cut them early in the morning when the flowers are refreshed and vigorous; but late in the fall, when the nights are quite cool, it is better to cut them in the evening, as they will open better in water in the house than on the plants when the temperature drops much below 50 degrees.

Editorial grouping. The practical pieces printed here appeared together in Broomall’s 1922 Dahlia Guide, but they belong to distinct recurring textual families rather than to a single historical work titled How to Grow Fine Dahlias. This edition groups them for reader convenience while preserving their individual headings and the 1922 text of each component.