Dahlias are known for their intense colors and symmetrical ball-like shape. They have been a hit across Europe since the late nineteenth century.

It was at the end of the eighteenth century before the Dahlia reached Europe and soon after three varieties were known. Between 1830 and I860 the interest in Dahlias became intense, and great premiums were paid for good varieties. Then in 1870 followed varieties that were flatter, less formed, and delicately colored. In 1872 a new species, Dahlia Jaurezii, was introduced. This is the progenitor of the Cactus Dahlia, a type universally admired.

The Cactus types are combined with the singles to”produce the Peony-flowered forms from which have been eliminated the week stems, resulting in an exalted form, and good, shaped blooms of matchless colors borne upon wonderfully strong plants. 

garden grown pink dahlias

Types of Dahlias

The American Dahlia Society’s classification of Dahlias may be of interest for reference: https://www.dahlia.org/guide/

Cactus Dahlias

A. TRUE, FLUTED TYPE: Flowers fully double; floral rays (“petals”) long, narrow, incurved or twisted, with sharp, divided, or fluted points and with revolute (“rolled back”) margins, forming, in the outer florets, a more or less perfect tube for more than half the length of the ray.

Typical examples: Snowdon, T. G. Baker, Mrs. Douglas Fleming, J. H. Jackson, H. H. Thomas, and Rev. T. W. Jamieson.

cactus dahlia

Hybrid-cactus or Semi cactus variety

Flowers fully double; floral rays (“petals”) short as compared with the previous type, broad, flat, recurved or twisted, not sharply pointed except when tips are divided (“staghorn”), margins only slightly revolute (“rolled back”), and tubes of outer florets, if any, less than half the length of the ray.

Typical examples: Master Carl, Perle de Lyon, Flora, Mrs. J. T. Mace, Kalif, and Rheinkoenig.

Decorative Dahlias

Double flowers, full to center in the early season, flat rather than ball-shaped, with broad, flat, somewhat loosely arranged floral rays “.petals”) with broad points or rounded tips which are straight or decurved (turned down or back), not incurved, and with margins revolute (rolled back) if rolled at all.

Includes forms like those of Souvenir de Gustave Douzon, Jeanne Gharmet, Le Grand Manitou, Delice, Lyndhurst, and Bertha Von Suttner, but does not include Le Golosse, Mrs. Roosevelt, Dreer’s White, Grand Duke Alexis, or similar forms, which fall into section B. of the ball-shaped double Dahlias.

Dahlias are a perfect addition to any garden and really make a home pop with a freshly cut lawn and a garden bed full of color.

Decorative Dahlias

Ball-shaped double Dahlias

A. SHOW TYPE: Double flowers, globular or ball-shaped rather than broad or flat, full to center, showing regular spiral arrangement of florets; floral rays more or less quilled or with markedly involute (rolled in) margins and rounded tips.

(The class called Fancy Dahlias is not recognized separately in this classification, but is included in this Sub-section A.)

Typical examples of Show Dahlias: Arabella, Dorothy Peacock, Gold Medal, John Walker, Colonist, and A. D. Livoni.

B. HYBRID SHOW, GIANT SHOW OR COLOSSAL TYPE: Flowers fully double, broadly hemispherical to flatly globular in form, loosely built so spiral arrangement of florets is not immediately evident; floral rays (“pet- als”) broad, heavy, cupped, or quilled, with rounded tips and involute (rolled in or forward) margins.

Typical examples: Grand Duke Alexis, Cuban Giant, Mrs. Roose- velt, Le Colosse, W. W. Rawson and Golden West.

G. POMPON TYPE: Shape and color may be same as of A. or B.; but must be under two inches in diameter.

Typical examples: Fairy Queen, Belle of Springfield, Darkest of All, Nerissa, Little Herman, and Snowclad.

Peony-flowered or Art” Dahlias

Semi-double flowers with an open center, the inner floral rays (“petals”) being usually curled or twisted, the other or outer petals being either flat or more or less irregular. Typical examples: Queen Wilhelmina, Geisha, Hampton Court, Mrs. W. Kerr, P. W. Janssen, and Glory of Baarn.

Peony flowered Dahlias

Duplex Dahlias

Semi-double flowers, with the center, always exposed on the opening of buds, with petals in more than one row, more than 12, long and flat, or broad and rounded, not noticeably twisted or curled. (Many so-called Peony-flowered Dahlias belong here.)

Typical examples: Big Chief, Souv. de Franz Listz, Merry Widow, Sensation, Prairie Fire, and Hortulanus Budde.

Single Dahlias

Open centered flowers, small to very large, with eight to twelve floral rays (“petals”) more or less in one circle, margins often decurved (turned down or back). There are no distinctions as to colors. The type embraces the large Twentieth Century as well as the smaller English varieties.

Typical examples: White Century, Golden Century, Scarlet Century, Newport Marvel (of the large-flowered forms); with Polly Eccles, Leslie Seale, Danish Cross and Ami Barillet (of the lesser flowered forms).

The Star singles and Cactus singles are omitted from the present classification scheme as not being sufficiently numerous or well defined yet.

Collarette Dahlias

Open centered blossoms with not more than nine floral rays (“petals”), with one or smaller rays, usually of a different color, from the heart of each ray floret, making a collar about the disk.

Typical examples: Maurice Rivoire, Souvenir de Chabanne, Diadem, Orphee, Madame Poirier and Albert Maumene.

Collarette Dahlias

Anemone-Flowered Dahlias

Flowers with one row of large floral rays (“petals”) like single Dahlias, but with each disk flower producing small, tubular petals.

Includes such forms as those of Graziella, Mme. Chas. Molin, Claude Barnard, and Mme. Pierre Dupont.

Miniature or Pompon Cactus

Small flowered, stellate fine petaled cactus Dahlias represented by Tom-tit, Mary, Nora, Minima. MIGNON OR TOM THUMB: Dwarf, bushy, single-flowered Dahlias for edging. A typical example: Jules Closson.

Bedding Dahlia

A taller, more upright type than the Tom Thumb. Typical examples: Barlow’s Bedder and Midget Improved.

Cockade of Zonal Dahlias

Single or collarette Dahlias, with three distinct bands ‘of color about the center. Type hardly known hi America, but includes forms such as those of Cockade Espagnole

Dahlia Cultivation

The Dahlia is typically Fall blooming and succeeds in any location where killing frosts do not come too early. If the plants are not seriously checked in their growth by frosts, they will usually bloom very nicely in most parts of New York State, New England, and the Central West. The soils best adapted to Dahlias are those which are somewhat -sandy, but they will grow on heavy clay. The regions which are influenced more or less by the ocean, that is, where cool nights are prevalent, are perhaps the most noted for Dahlia growing, especially Long Island, New Jersey, Rhode Island, Maryland, and Massachusetts in the East, and without a doubt, the best Dahlias we have ever seen were in British Columbia, Northern California, Washington and Oregon. Heavy soils may be lightened by coal ashes. Sand and lighter soils will benefit from manure to make them more moisture-retaining. Nitrogenous fertilizers are rarely applied because they cause too great vegetative growth and a retarding of the flowering period.

Starting Dahlia Tubers

The tubers should be started about April 1st in a warm, lightroom, merely placing them in a shallow box of sand or light soil. When the young shoots begin to show, they should be so cut that one or two eyes are allowed to remain on each piece; the eyes start from the collar.

To Attain Large Flowers

If the soil is carefully and diligently cultivated there will be little need for watering, which is detrimental unless consistently practiced. Thorough watering should be given each time and at regular intervals; otherwise, plants will be checked and flowers will suffer.

In order that each individual flower may be as large as possible, especially in the case of the show and fancy types, which produce a great many flowers of medium size, it is best to disbud the main branches leaving only the terminal bud. It is often best to allow only six or eight branches. The singles, collarettes, and pompons are rarely pruned or disbudded, the idea is to get plants with as many flowers as possible. The cactus varieties are apt to have their weak neck habit intensified by excessive pruning and de-budding so that they should be cautiously disbudded, removing only part of the buds.

Flowers are best cut in the morning or evening and any foliage not wanted should be removed. The stems should then be placed in water up to the base of the flowers and removed to a cool place. Hard-stemmed varieties are best placed in hot water and allowed to remain until the water cools when they should be removed to fresh cold water. Under no circumstances attempt to ship for exhibition without the pre-cooling.

Why You should grow Dahlias

Dahlias will always make a successful appeal to the affections of the amateur gardener, first because of the comparative simplicity of its culture, but chiefly because, at a period of the year when the summer denizens of the flower garden are beginning to bear traces of wear and tear, and are preparing either for their winter rest or their demise, the dahlia is just coming into bloom.

If the weather is at all propitious, there is a certainty that it will produce a wealth of gorgeous flowers over a period of many weeks and that it will help to make the early autumn garden gay until the first severe frost pronounces its doom.