All About Dahlias~Form

Inland Empire Dahlia Society

Affiliate of the American Dahlia Society and the Pacific Northwest Dahlia Conference

There are currently 19 forms of dahlias listed in the 2009 ADS Classification Book.

Clearview David          308 BB FD L

Formal Decorative: Ray florets are generally flat, broad, and smooth in a regular arrangement that gradually recurve toward the stem. Each ray floret row should convey uniform and regular size arrangement with the tips preferably round or extending to a slight point. The ideal depth is three quarters the diameter of the bloom and should not be greater than its diameter

Vassio Meggos                   128 A ID LV

Informal Decorative: Ray florets are twisted, curled, or wavy, and of uniform size in irregular arrangement.  They may be partially involute or revolute but no portion should be fully revolute or involute except at the tip of the ray floret. The ideal depth is three-quarters the diameter of the bloom and should not be greater than its diameter.

Semi-Cactus: Ray florets are broad at the base, straight or incurved, and reflex toward the stem in a regular and uniform arrangement. Ray florets will be revolute for approximately half their length and fully revolute (touching or overlapping) for at least one-fourth their length. The ideal depth is three-quarters the diameter of the bloom and should not be greater than its diameter.

Straight Cactus: Ray florets are narrow at the base, straight, uniform in length and reflex toward the stem, radiating uniformly in all directions from the center. They will be revolute for the majority of their length and fully revolute (touching or overlapping) for approximately half their length. A depth of about three-quarters the diameter is ideal for the form.

 

Incurved Cactus: Ray florets are pointed, uniform in length, they uniformly curve toward the face of the bloom, are revolute for the majority of their length and are fully revolute for at least half their length. Because ray florets curve toward the face of the bloom, they usually lack the depth of the preceding dahlia forms. A depth of one-half the diameter or slightly more is ideal for this form. Although the general direction

of the ray floret is up and away from the stem, there may be an arc to the rays downward and then up. The involute is rarely if ever covered.

Laciniated Dahlias: Ray florets are split at the tip with the number and depth of the splits varying according to the size of the ray floret. The portion of the ray floret with the splits should uniformly twist or curl whether involute or revolute. The less mature ray florets should possess splits but do not have to twist or curl in the ideal laciniated dahlia, the majority of ray florets will be uniformly arranged with a split, twist, or curl that conveys an overall fringed or frilled affect. Ray florets, slightly involute or revolute, that split regardless of length and remain generally flat are a major fault.

Ray florets with a shallow notch or cleft and possessing little twisting to the extreme portion should not be classified as laciniated. The ideal depth is three-quarters the diameter of the bloom and should never be greater than its diameter.

Kenora Jubilee             141 A SC W

Kathy’s Choice            462 M C Y

Camano Rascal            275 B IC BI R/W

Colwood Scheri           294 BB FD V

BALL Dahlias: Blooms are ball shaped with uniform florets, involute for most of their length, and fully involute for more than half the length; the ray florets reflex toward the stem. Ray floret tips in cross section should be circular and exhibit little distortion, completely filling the floral head and are either round or blunt without notch or point.

Cornel               507 BA DR

MINIATURE BALL Dahlias: Except for size, miniature ball and ball dahlias possess the same form features.

Hy Suntan        531 MB BR

POMPON Dahlias: The ray florets are involute for the whole of their length and fully involute for half their length. Except for size they are similar to the ball description.

Pearson’s Michelle       543 P OR

STELLAR Dahlia—Ray florets break gradually from immature florets to fully developed outer ray florets. The outer florets should be narrow and involute with a slight recurve to the stem. The less mature florets should possess the same narrow and partially involute characteristic. The depth of the stellar form should be one-half to two-thirds the diameter of the bloom, the greater depth being ideal.

Alloway Candy            564 ST PK

WATERLILY Dahlia: The bloom should be fully double and symmetrical; the side view should be flat to saucer-shaped in arrangement, and the layer of florets should be open faced to give a delicate appearance. The center should be closed and dome-shaped breaking gradually to four to seven rows of fully developed outer florets. Outer florets should be broad and slightly cupped with rounded tips. A bloom position at 45 degrees is preferred, but a top facing bloom is acceptable. In petite waterlily

cultivars (from 1 to 3 inches) in diameter, the depth should contain fewer rows of ray florets in order to represent the waterlily form accurately. The depth should never be more than one-half the diameter

of the bloom.

Pam Howden                 610 WL LB

PEONY Dahlias: At least two, but not more than five rows of ray florets surround the disc. Ray florets are broad, generally flat to slightly cupped and evenly spaced in a flat plane. Ray florets are equal or nearly equal in length from the bloom face to the back, not recurving or reflexing to the stem. Ray florets adjacent to the disc may be twisted or curled, but if present should be symmetrically arranged around the disc. Ideal depth is less than one-third the diameter. Disc florets may

show zero to two rows of pollen.

Elvira                 625 PE DP

ANEMONE Dahlias— A dome of elongated tubular disc florets surrounded by one or more rows of ray florets. The ray florets should be uniform in shape, size and formation and be regularly arranged around the sisc florets. The ray florets should be visible from the face of the bloom, creating a pleasant and balanced framing of the dome. The disc florets should also be uniform in shape, size and formation and be fully developed. Each disc floret should be entirely tubular or predominantly tubular with a fringed tip.

Azuma Kagami            647 AN DR

COLLARETTE Dahlias—A bloom will have a single row of flat or slightly cupped ray florets arranged in a flat plane; the ray florets will uniformly overlap, preferably in the same direction with no gaps. The petaloids surrounding the disc should be approximately one-half to two-thirds the length of the ray florets. Eight ray florets are most desirable. A round floret tip is preferred. The disc flower should contain evidence of pollen with up to three rows desirable.

Pale Tiger         671 CO BR

SINGLE Dahlias—The bloom has a single row of flat or slightly cupped ray florets arranged in a flat plane. They uniformly overlap, preferably in the same direction with no gaps. Eight ray florets are most desirable. Disc flowers with up to three rows of pollen are desirable. A round floret tip is preferred. The bloom is over two inches in diameter.

Northwest Cosmos       708 S L

MIGNON SINGLE Dahlias—Mignon single dahlias possess the same formation as single dahlias except they have round ray floret tips. Disc flowers should have no more than two rows of pollen.

Daisy                 725 MS DP

ORCHID Dahlias—A single row of uniform, evenly spaced ray florets arranged in a flat plane surround the disc flowers. The ray florets should be straight and involute for two-thirds or more of their length and fully involute for at least one-third their length. Eight ray florets are most desirable. Disc flowers with

up to three rows of pollen are desirable.

Dandie Trish    752 O FL

NOVELTY OPEN Dahlias—Dahlias with characteristics distinct and different from the present classifications are classified as novelty dahlias. The center should be open with the disc center in proper proportion to the ray florets.

Alpen Imp        764 NO PK

NOVELTY FULLY DOUBLE Dahlias—Dahlias with characteristics distinct and different from the present classifications are classified as novelty dahlias. The center should be closed.

Valley Porcupine         790 NX LB