Commercial Floriculture

Importance and Uses

• They are extensively used in exhibition, garden display and home decoration
• Dwarf types are suitable for beds, borders and mixed borders shrubbery.
• Large flowering dahlias grow in pots, terraced roof and verandah display.
• Long stemmed one is used for flower arrangement.
• Cut flowers of pompons, small and miniature type are most suitable for vases and
• Also used for making garlands.
• Tubers of dahlia contain some medicines like, insulin, fructose, phytin & benzoic acid etc,.

Origin and History
The native land of dahlia is Mexico. National flower of Mexico.
The species introduced into the old world are Dahlia imperialis, D. coccinea, D. merckii and D. juarezii.
The later is actually a hybrid of D. variabilis from which most of the garden types have been developed and due to continues crosses several present day types are evolved.

Morphology
Dahlias are half hardy perennials with tuberous roots.
Stems are mostly erect, branched, glabrous or scabrous.
Leaves 1-3 pinnate, with slightly serrated margin, are produced opposite at each node on the stem.
Bears flower on the long, stiff stem well above the foliage.
Ray florets are neutral or pistillate and disc florets perfect.

^Top

Classification
Dahlias are classified according to flower shape and arrangement of petals by National Dahlia Society of England.

I. SINGLE-FLOWERED:
These have one row of petals, generally grow to 3 feet or less, and have flowers 4 inches (10 cm across) or less in diameter.

II. ANEMONE- FLOWERED:
Flowers have one or more rows of petals surrounded by a dense group of long tubular disc florets.
Fully double flowers and good for flower arrangement.

III. COLLERETTE:
• Flowers have one row of normal petals and one or more rows of small petals (the collar).

Discs are apparent, very good for flower arrangement.

IV. PAEONY FLOWERED:
Flowers have two or more rows of generally flattened petals.
Discs are apparent.

V. DECORATIVE:
Have fully double flowers.
The petals are broad, more or less flat or slightly twisty and wavy.
The tips of the petals may either be rounded or pointed.
It is the largest group among dahlias.
Decorative group is further divided according to size into five groups.
Giant Decorative
Large Decorative
Medium Decorative
Small Decorative
Miniature Decorative

^Top

VI. BALL
Have fully double flowers.
They are ball shaped or slightly flattened. They are sub divided into
1. Small ball (4.0 to 5.9 inch)
2. Miniature ball (2.0 to 4.0 inch)

VII. POMPON:
Have fully double blooms.
Blooms are globular in appearance like table tennis balls.
The size limit is 50mm.

VIII. CACTUS:
Have fully double blooms. Outer petals are narrow preferably with revolute edges overlapping from the tips for at least two third of their length.
This is a large group and is further divided into five sub groups.
1. Giant cactus
2. Large cactus
3. Medium cactus
4. Small cactus
5. Miniature cactus

IX. SEMI CACTUS
Have fully double flowers. Like decorative dahlias the half base of the petal are broad and flat.
The other half of the outer petal is revolute from the pointed tip for more than one quarter but less than half of the full length.
This group is also divided into five sub-groups.
i. Giant semi-cactus
ii. Large semi-cactus
iii. Medium semi-cactus
iv. Small semi-cactus
v. Miniature semi-cactus

^Top

X. MISCELLANEOUS:
Cultivars which do not fall under any of the main nine groups are grouped under this category.
Good for flower arrangement.

XI. FIMBRIATED:
Fully double flowers.
Petals are fimbriated from the tips preferably for at least 10 mm.

XII. WATER LILY
Flowers are fully double.
Outer petals are broad and slightly cupped with rounded ends. From the side view the bloom are look like a saucer.
Flowers resembles water lily (nymphaea).

XIII. STAR FLOWERED
Small cupid shaped flowers having two or three rows of pointed petals which overlap very slightly.
 

^Top