Dahlias For the Home (1923)

No flower is more important in the garden during the late summer and autumn than the dahlia. Its needs are simple and its returns are many and generous.

If grown in a situation open to sunlight and fresh air but not swept by winds and if provided with a well-worked fertile soil, neither over watered nor parched, the dahlia will provide an abundance of beautiful blooms for cutting or garden display.

The forms and color variations of the flowers furnish such a great range that almost any personal taste or fancy can be gratified.

Dahlias are obtained from nurseries as dormant roots or as growing plants which have been raised from cuttings. Plants may also be raised from seed.

After the season's growth the plants are dug and the tops cut off, the tubers—which used to be referred to as simply “roots”—can be dried and stored until the following spring in a dark, dry, frost-proof cellar.

In the spring, these tubers are ready to be started into growth and divided into as many pieces as desired or as there are new shoots starting.

To the commercial grower the dahlia is of importance in providing an abundant supply of flowers through the late summer and autumn in a large variety of colors and forms and of a substance and quality which make them "good shippers and keepers," in the parlance of the trade. 

To one who makes a garden for its effect as a whole the dahlia is of importance for its range of color, its freedom of bloom, and the dominating character of its appearance in the autumn garden. 

To the amateur with whom collecting is a hobby the dahlia offers a field of almost endless variety. Ever since these flowers were brought to garden notice in 1789 they have shown an amiable tendency to vary from seed into multitudinous colors and forms. 

To that amateur who takes pleasure in producing his own garden plants the dahlia proves an admirable subject for his care, as dahlias are easily raised from seed and come quickly to their flowering.

While the dahlia is preeminently a plant flourishing best along the coasts where the air is filled with moisture, it can be grown with entire success at a considerable distance inland if the grower is willing to take particular pains with the water supply of his plants. Careful watering, the extent of which can be determined best by experiment, will show just how much water will be required to keep the plants in vigorous but not sappy growth. 

With this must be considered the cooling influence of a deep mulch, whether supplied by cultivation or by outside materials. Remembering this, the gardener even in the interior of the country should be able to produce dahlias of considerable merit, when the cooler nights of autumn assist his work, though for a shorter season and of less perfect development than if his garden were in a more favored locality. 

This handicap should be borne in mind, especially in purchasing from the catalogs of growers located in the best dahlia regions, for often the flowers from their plants when grown in less favorable situations fail to realize the mammoth size and remarkable colorings promised, simply for lack of an ideal location. 

There is one difficulty, however, which the gardener can’ overcome, and for the man who lives in a Northern State where the frosts come early dahlias are scarcely worth the effort to bring them to early maturity, although it has been pointed out that they will grow wherever tomatoes will succeed. 

With all this in mind, it is not difficult to see how a plant so easily cared for, in localities at all suited to its growth, should have come into such general popularity.

Dahlia history commences in 1791, when Cavanilles, the director of the Botanic Garden of Madrid, Spain, described in the first volume of his Icones the flowering of a set of dahlia roots (not seeds) received in 1789 from Vicente Cervantes, of Mexico. 

It has been reported for years that some of this shipment found its way directly to England through the hands of Lady Bute, wife of the British Ambassador to Spain. Actually, it has recently been pointed out by careful historical research that dahlias first reached England in 1798 through the agencies of a lady who should be known by her correct title, the Marchioness of Bute. 

This had little effect on the history of the plant, however, as all these plants perished from a lack of proper understanding of their needs. 

They were reintroduced successfully in 1804, through the interest of Lady Holland. On the Continent, the plants, both single and double varieties, flourished and in time were widely distributed from Madrid. 

In the garden of M. Donkelaar, director of the Botanic Garden of Louvain, some fine double forms appeared, which were the important beginnings of the double dahlias of later years.

It has recently been brought out that while this importation was the introduction of the living plants to Europe, knowledge of their beauty and forms was reported as early as 1575 by Francisco Hernandez, the celebrated protomedico of Philip It. 

He described them as being cultivated in Mexico, cited local names for several forms, and in addition noted their range of colors and degrees of doubling. His descriptions, however, were not published until much later.

With this information it is easy to understand how seedlings raised in Europe from the original tubers showed immediate and considerable variations. The reason is that the original tubers probably represented not only the variable species but garden or natural hybrids in addition.

Merging into this last group is the group of hybrid cactus dahlias (fig. 5) in which the petals do not show the extreme of reflexing characteristic of this type. Indeed, some have petals which are reflexed scarcely more than at the margins (fig. 6). They are flowers of great beauty and of greater commercial importance, as they ship better and hold their flowers more erect than the true cactus types.

There are, however, various other types of dahlias. 

The original single type (fig, 1) has been maintained and developed with plain and cactus types of petals in many colors and in greater size. 

More recently has appeared the anemone-flowered dahlia (fig. 9), in which all the disk florets are partially transformed, as in an anemone-flowered chrysanthemum. These, together with such types as the pompon dahlias, which are merely dwarf forms similar to the tall growing show dahlias (fig. 10), but with more spherical flowers, are the chief sorts to be met with. 

Each year brings its train of novelties, among which are often new strains perfected by some grower and possessing more or loss distinction.

Dahlias are easily propagated. The amateur usually buys tubers in the first place. These may be either dormant tubers or young growing plants. He may, however, purchase seed and raise his own plants.

SEEDS.

Dahlia seed is usually planted indoors several weeks before the time of the last killing frost, and the young seedlings are pricked off into pots when large enough to be handled. They are then transferred to their permanent quarters as soon as danger from frost is past. 

With good culture these come into full bloom as quickly as the sorts planted from tubers. It is well to remember, however, that dahlias do not come true from seed. There is a tendency to revert to sem-idouble or single forms, and that at best the flowers are often disappointing.

CUTTINGS.

Growing plants, especially of the new and rarer sorts and also of varieties which do not multiply freely by division of tubers, are commonly supplied by the trade. These are raised from cuttings. This is work for the commercial grower rather than the amateur, as it involves more equipment than the amateur commonly has at his disposal.

[Editor’s note: This is not true. Dahlias are easily propagated from cuttings. Take a look at some articles in the Dahlia Doctor Knowledge Center to learn how it’s done.]

The dormant tubers are planted closely in a greenhouse in January. When the young shoots have reached 4 to 6 inches in length they are cut off for cuttings. They are cut between the first and second pairs of leaves, so that new shoots will spring up to take their place. These, in turn, may be cut off and made into cuttings, but they do not have the vigor of the first set.

DIVISION OF TUBERS.

The clumps of tubers should be started into growth so that the location of all the eyes can be seen. This can be accomplished by putting them in a warm moist place without soil for a short time. 

If the dahlia makes tubers of excessive size, many growers recommend cutting off part of the individual tuber. There is no benefit to the young plant if the tuber is too large, and there is greater advantage in having tubers of uniform smaller size.

As with any other plant, there are certain dangers in over propagation of the dahlia. For this reason it is never advisable to take more than two sets of cuttings from a root, as the shoots following those first taken rarely make vigorous plants. The following season these plants propagated from cuttings should not be used as stock to produce new cuttings, but the tubers should be divided moderately.

The result of over propagation is a stock of poor vitality, producing plants of little vigor and flowers few in number and of poor quality.

Dahlias are commonly grown in masses by themselves rather than singly in garden beds of mixed flowers. There is no reason why they should not be grown as specimens in the border, save that the facility with which they can be handled in beds by themselves or in rows in the vegetable garden has made that the usual practice. 

Dahlias respond best to open culture with abundant air and sunlight. They should not be subjected to high winds, which break the stiff canes and beat the heavy blooms about.

Dahlias can be raised in almost any kind of soil, provided they are given the food they need. They are tolerant of many kinds of soils and grow in many situations. The soil should be well drained, however, and should approximate what is known as good garden soil. 

Such a soil is rich in plant food and of a light and friable texture, conditions existing naturally in some localities, but usually attained by good cultural practices of fertilization and tillage through many years. 

In poor soil the plants are stunted, while in soil which is too rich they produce too much growth with a minimum of flowers. For these reasons the cultivator must apply fertilizers with care.

Most growers prefer to plant in garden soil of the type described without recourse to additional fertilizers until late summer. In the vicinity of Washington, D. C, a mulch of strawy manure is applied in mid-August, which cools the soil and furnishes extra food to the plants. In addition, a fertilizer rich in potash may be added if the plants show any sign of stopping growth. 

It is essential, however, that there should never be an excess of stimulation, as the result is always an increase of leaves and not of flowers.

Dormant tubers can be planted as soon as all danger of frost is past, and green plants somewhat later. Dormant stock is sometimes held for planting until June without any difficulty except that of continued storage. 

Late planting is absolutely necessary in the South, because unless delayed in growth the plants would reach maturity in midsummer. In that case, the stems would harden up, and the growth become so stunted that few if any flowers would result.

After preparing the soil as directed, the tubers should be set in the field in rows 3 to 4 feet apart and as far apart in the row as is desired. If the plants are arranged so that they do not come opposite each other in the rows, but are staggered, some space is saved. 

Plants spaced equidistantly in this way or in a rectangular plan produce finer specimens than those crowded in the row, and when so planted can be given extra food and care with resulting flowers of finer size and quality. 

The plants should be kept well and deeply cultivated until blooming commences. After that ordinary tillage is sufficient. This treatment is better than any amount of water, as it produces normal rather than sappy growth.

If the clump of tubers has been skillfully cut apart there will be but a single shoot, but if other shoots appear they should be removed, in order to throw all the strength of the plant into the main stem. 

[Editor’s note: Modern dahlia practices suggest leaving multiple stems, up to perhaps six or so.]

Practice varies somewhat in the training of young dahlias. Some growers remove the top of the single shoot at once to induce the formation of several stems and a dense bushy habit. Others prefer to let the shoot develop naturally to its terminal flower, which they cut with a long stem. 

If branching has not commenced naturally before this cut, it is immediately induced. The chief advantage of this practice is that this first flower, if produced in good season, is often the best flower produced by the plant.

As the plant develops it should be tied to the stake with some material soft enough not to cut the tender stem, securing both the main stem and the side branches. Experience alone will guide the grower in determining the best number of side shoots to leave in each variety. 

By late summer the plant should have reached almost its full development and may begin to show flowers. If permitted to develop they often give blooms of fair size, but rarely of as large size or as good quality as those produced later in cooler weather. For this reason it pays to remove all the early buds until the approach of cooler weather, the end of August in the Middle Atlantic States, from which time they may be permitted to develop normally.

A certain amount of disbudding can be practiced to bring about extra-large blooms, as for chrysanthemums. These flowers are often of enormous size and are more striking for exhibition than for garden decoration. Where blossoms with 2-foot stems and monstrous flowers are not required or needed, disbudding is not necessary. Disbudding will not reduce the ultimate flowering, as it causes growths to break out from lower joints on the stalks.

If the cellar is too warm or too dry—a common difficulty—the roots can be stored in barrels filled with dry sand or sawdust. Care must be taken that the storage material is perfectly dry, as otherwise rot will set in and damage the entire mass. 

On the other hand, there is a degree of dryness which must be avoided, as it causes the tubers to shrivel and makes starting difficult the following spring. Again, the greatest care must be exercised that none of the tubers for storage are injured in any way, as the decay which starts in a wound caused in digging will soon spread to healthy tubers, often causing a total loss.