The various varieties of Dahlia flowers
A joint Dahlia Committee formed by selecting members from National Dahlia Society and Royal Horticultural Society in Britain has classified modern dahlia into 10 forms. Shape of the flowers, flowering patterns and resemblance to other flowers form the basis of classification.
1. Single-flowered Dahlias
An open faced dahlia with one or two rows of evenly spaced ray florets surrounding the disc flowers. The blooms hardly exceed 10cm in diameter and plant height of about 30 cm. They are perfect for bedding purposes.
2. Anemone-flowered Dahlias
Dahlias with one or more rows of ray florets surrounding a dense group of elongated tubular disc florets. Blooms are 7.5 cm across and plant height 60-90 cm.
3. Collerette Dahlias
An opened faced dahlia with an inner ring of short florets, the ‘collar’ and an outer row of flat ray florets. Plant height about 110 cm; blooms 10-15 cm across and are perfect for cutting.
4. Waterlily Dahlias or Nymphaea- flowered
Fully double blooms with broad and openly faced or slightly cupped ray florets, giving a flat or saucer- shaped appearance to the flower. The centre of the flower is closed and dome shaped. About 90 cm high; blooms 10-12 cm across.
5. Decorative Dahlias
Fully double blooms, ray florets may be flat, partially revolute (petal edges roll back), or partially involute (petal edges roll forward) or twisted and apex with a blunt point. Plant height 90-150cm. In U.S. decorative dahlias are split into 2 sub-groups. Formal Decorative- The petals are in a regular arrangement. Informal Decorative- Ray florets are long, twisted and irregular in arrangement.
6. Ball Dahlias
Blooms are ball or globose shaped, slightly flattened at the top. Ray florets blunt or rounded at the tips and cupped for more than half of their length. Bloom size 10-15 cm across, miniature ball dahlias up to 10 cm across.
7. Pompon Dahlias
Sometimes called ‘drum-stick’ dahlias, similar to ball dahlias but more globular and smaller in size, with ray florets involute for their entire length; up to 90 cm in height and blooms 5cm across.
8. Cactus-Flowered Dahlias
These types have fully double blooms without any central disc. Ray florets are long, pointed and part of the petal is revolute. Cactus, semi-cactus as well as decorative groups are subdivided by size. In U.S. the cactus group is further divided into 2 groups-straight cactus and incurved cactus.
9. Semi-Cactus-Flowered Dahlias
Ray florets are broad at their base, revolute for less than half their length, and either straight or incurving. Plant height is about 120 cm.
10. Miscellaneous Dahlias
These include Chrysanthemum type Dahlias, Orchid Dahlias, Star Dahlias and Peony-flowered.
Dahlia colors
The National Dahlia Society recognizes 14 different colours or colour combinations of dahlias, except a true blue colour. They are:
1) White
2) Yellow
3) Orange
4) Bronze
5) Flame
6) Red
7) Dark red
8) Light pink
9) Dark pink
10) Lavender, lilac or mauve
11) Purple or violet
12) Blends - a blending of two or more colours like pink, yellow, lavender.
13) Bicolored - blooms with two distinct colours.
14) Variegated – several colours appear in one bloom either in dots, splashes or stripes.
SIZE
The National Dahlia Society has adopted size divisions, lettered A to E -
A - (Giant), blooms over 10 inches in diameter
B - (Large), blooms over 8 to 10 inches in diameter
C - (Medium), blooms over 6 to 8 inches in diameter
D - (Small), blooms over 4 to 6 inches in diameter
E - (Miniature), blooms up to 4 inches in diameter