''Dahlia pinnata'' (''D.'' × ''pinnata'') is a species in the genus ''

Dahlia Dahlia (, ) is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico and Central America. A member of the Asteraceae (former name: Compositae) family of dicotyledonous plants, its garden relatives thus include the sunflower, ...

'', family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

, with the common name garden dahlia. It is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the genus and is widely cultivated.

Description

''Dahlia pinnata'' is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

plant with a

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

and

tuberous Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growin ...

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...

s, reaching a height of 70 to 120, rarely 160 centimeters. The stem is erect being branched only in the inflorescence. The leaves are usually simple, with leaflets that are ovate and 5–10 cm long. The plant is slightly shaggy. The two to eight flower heads have a diameter of 6 to 10 centimeters on 5 to 15 centimeters long stems. The eight florets have a length of 3 to 5 centimeters, are ovate and coloured pink to deep purple. Dahlias are mid-year to late-year season flowers that grow in a lot of various colors and forms.

Taxonomy

Hansen and Hjerting in (1996) demonstrated that ''Dahlia pinnata'' should more properly be designated ''D. x pinnata''. ''D. x pinnata'' was shown to actually be a variant of '' D. sorensenii'' that had acquired hybrid qualities before it was introduced to Europe in the sixteenth century and formally named by Cavanilles.Cavanilles, A. J. 1791. Icones et Descriptiones Plantarum 1: 57. The original wild ''D. pinnata'' is presumed extinct.

Distribution and habitat

It is, geographically, located in Northern/ Central America and they tend to grow at borders. The plant occurs in Mexico in the mountains around

Mexico City Mexico City ( es, link=no, Ciudad de México, ; abbr.: CDMX; Nahuatl: ''Altepetl Mexico'') is the capital and largest city of Mexico, and the most populous city in North America. One of the world's alpha cities, it is located in the Valley o ...

Ecology

The flowering period extends from July to October.

Pests and diseases

Dahlias tend to attract quite a bit of insects, some which are dangerous and harmful to their survival. Insects like

slug Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...

earwig Earwigs make up the insect order Dermaptera. With about 2,000 species in 12 families, they are one of the smaller insect orders. Earwigs have characteristic cerci, a pair of forcep-like pincers on their abdomen, and membranous wings folded ...

s, the

red spider ''Tetranychus urticae'' (common names include red spider mite and two-spotted spider mite) is a species of plant-feeding mite generally considered to be a pest (animal), pest. It is the most widely known member of the family Tetranychidae or spi ...

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastro ...

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sym ...

aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...

s, and

thrips Thrips ( order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...

threaten dahlias because they can eat the petals, leave slime trials, leave tattered petals, etc. Dahlias can also become infected with the following diseases: Sclerotinia disease,

fungal diseases Pathogenic fungi are fungi that cause disease in humans or other organisms. Approximately 300 fungi are known to be pathogenic to humans. Markedly more fungi are known to be pathogenic to plant life than those of the animal kingdom. The study of fu ...

mildew Mildew is a form of fungus. It is distinguished from its closely related counterpart, mould, largely by its colour: moulds appear in shades of black, blue, red, and green, whereas mildew is white. It appears as a thin, superficial growth consi ...

, Botrytis,

Crown Gall ''Agrobacterium'' is a genus of Gram-negative bacteria established by H. J. Conn that uses horizontal gene transfer to cause tumors in plants. ''Agrobacterium tumefaciens'' is the most commonly studied species in this genus. ''Agrobacterium'' i ...

, etc. If dahlias do become infected with these they can wilt, have spots on the leaves, the leaves can get irregular coloring/ patterning, etc.

Cultivation

Used as an ornamental plant, and was cultivated by the

Aztecs The Aztecs () were a Mesoamerican culture that flourished in central Mexico in the post-classic period from 1300 to 1521. The Aztec people included different Indigenous peoples of Mexico, ethnic groups of central Mexico, particularly those g ...

before the discovery of America, and was introduced to Spain in 1798. Modern dahlias are often the product of hybridisation between ''D. pinnata'' and D. coccinea. As cutflowers, dahlia have a long lifespan. Besides being used for their outside appearance, dahlias tend to be used for their medicinal properties as well. This plant's roots contain some "nutritious inulin stored inside them" and they even have "antibiotic compounds concentrated in the skin of the tubers." This was so much so that this garden dahlia was before such an "important root crop and medicinal plant among the pre-Columbian Indians of central Mexico, Yucatan and Guatemala." Dahlias prefer rich soil (pH level estimated at around 6.5- 7.5) with enough organic matter. The roots must be kept moist since they are very shallow rooted which means they usually become dry fairly frequently and quickly. They bloom around mid-summer through the beginning of winter, they are able to survive a light frost, but anything colder/harsher than that, they will not be able to keep thriving. When the harsh weather of winter is approaching, the dahlias should be dug up and stored in a safer place for them. Many dahlia pinnata types can grow from seeds but more often they are cultivated by division of the tuberous roots or by stem cuttings. Providing the flower with some kind of plant food (mulch, growing media, nutrient food, etc.) can really make the dahlia healthier and more likely to survive.

References

External links

Global Compositae Checklist

Catalogue of Life

Tela Botanica
{{Taxonbar, from=Q1549236 pinnata Endemic flora of Mexico Flora of Central Mexico Garden plants of North America Plant extinctions since 1500 Taxa named by Antonio José Cavanilles