Dahlia pinnata

Dahlia pinnata

The garden dahlia (Dahlia pinnata Cav. 1791) is a herbaceous species belonging to the Asteraceae family.

Systematics –
From the systematic point of view it belongs to the Eukaryota Domain, Kingdom Plantae, Magnoliophyta Division, Magnoliopsida Class, Subclass Asteridae, Asterales Order, Asteraceae Family and therefore to the Dahlia Genus and to the D. pinnata Species.
The terms are synonymous:
– Bidens variabilis (Willd.) Baill.
– Coreopsis georgina Cass .;
– Dahlia barkeriae Knowles & Westc.
– Dahlia crocata Lag.
– Dahlia purpurea Poir .;
– Dahlia rosea Cav .;
– Dahlia sambucifolia Salisb .;
– Dahlia superflua (DC.) WT Aiton;
– Dahlia variabilis (Willd.) Desf .;
– Georgia superfluous DC .;
– Georgia variabilis Willd .;
– Georgina superflua DC .;
– Georgina variabilis Willd ..

Etymology –
The term Dahlia of the genus was dedicated by Abbot Antonio Jose Cavanilles, director of the Royal Gardens of Madrid who had received the first samples from Mexico in 1791, to the Swedish botanist Anders Dahl (1751-1789), a pupil of Linnaeus (David Hollombe, pers. comm.).
The specific pinnata epithet comes from pínna pen, feather: with the shape of a feather or, by extension, winged.

Geographic Distribution and Habitat –
Dahlia pinnata is a plant native to North America, where it grows both in the southernmost parts, on the border with Mexico, and in the mountains around Mexico City.
Its habitat is that of dense forests of oaks and pines at an altitude of about 1,800 meters s. l.m.
It is the type species of the genus and is widely cultivated.

Description –
Dahlia pinnata is a perennial herbaceous plant that has a rhizome and tuberous roots.
The plant reaches a height ranging from 70 to 120 and more rarely up to 160 centimeters. The stem is erect as it is branched only in the inflorescence.
The leaves are generally simple, with oval leaflets and 5-10 cm long. The plant is slightly shaggy.
It bears two to eight flower heads that are 6 to 10 centimeters in diameter on 5 to 15 centimeters long stems. The flowers have a length of 3 to 5 centimeters, are oval and colored from pink to deep purple.
The flowering period is from July to October.

Cultivation –
They are plants that prefer a rich soil (pH level estimated at around 6.5-7.5) with sufficient organic matter. The roots need to be kept moist as they have very shallow roots which means they usually dry out quite frequently and quickly. They bloom around mid-summer through early winter and are able to survive light frost but not persistent cold conditions.
When harsh winter weather approaches, the rhizomes of dahlias should be collected and stored in a suitable location.
Many types of dahlia pinnata can grow from seeds but are more often grown by division of tuberous roots or stem cuttings.

Customs and Traditions –
According to Hansen and Hjerting (1996), Dahlia pinnata should be more properly designated D. x pinnata as it has been shown to be indeed a variant of D. sorensenii which had acquired hybrid qualities before being introduced in Europe in the 16th century and formally called da Cavanilles. Among other things, it is assumed that the original wild D. pinnata is extinct.
Dahlia pinnata is an ornamental plant, cultivated by the Aztecs before the discovery of America, it was introduced in Spain in 1798. Modern dahlias are often the product of the hybridization between D. pinnata and D. Coccinea.
The reason why dahlias are used as ornamental plants and for their flowers is because there are around thirty species that are all known for their immense beauty and ability to survive once cut. The lifespan of the flowers, once cut, is superior to most other flowers, especially if they are kept in clean water with enough nutrition to keep them healthy. They have also become crucial for many plant growers, particularly because of their appearance, durability, and ability to reproduce easily.
Dahlia pinnata, in addition to being used for its external appearance, also tends to be used for its medicinal properties. The roots of this plant contain nutritional inulin and also have antibiotic compounds concentrated in the skin of the tubers. Such properties were already known among the pre-Columbian Indians of central Mexico, the Yucatan and Guatemala.
Among the uses of this plant, in addition to the ornamental ones, it should be remembered that the flower petals are used in salads. The roots are cooked and eaten as a vegetable. They taste bitter.
A sweet part called “dacopa” is extracted from the tubers, which is used as a drink or as an aroma. It is mixed with hot or cold water and sprinkled with ice cream. Its smooth, naturally sweet taste is said to combine the characteristics of coffee, tea and chocolate.
Since the root is rich in a starch that is inulin, which even if it is not absorbed by the body, can be converted into fructose, a sweetener suitable for diabetics.
An orange dye is also obtained from the flowers and seed heads.

Preparation Method –
Dahlia pinnata is used, as mentioned, as well as for ornamental purposes also in the food field where the flower petals are used in salads while the roots are cooked and eaten as a vegetable.
Dacopa is extracted from the tubers and is used both as a drink and as an aroma; this is mixed with hot or cold water and sprinkled with ice cream.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (edited by), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Warning: Pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not represent in any way a medical prescription; therefore no responsibility is taken for their use for curative, aesthetic or food purposes.