Dahlias are cut flowers obtained from herbaceous plants of the genus Dahlia, known for the first time in Mexico. It is a plant with a herbaceous stem with a bushy and epiphytic growth habit. At present, around 30 species of the genus have been identified. Dahlia and some 20.000 species have been obtained through horticultural crosses that are certified in the International Dahlias Registry. I invite you to continue knowing in this article about Dahlias.
Las Dalias
Dahlias are a herbaceous stem plant that when it blooms produces a flower with many petals that is distinguished by having different colors, it is characterized by having quite strong roots, with many stems and leaves that look like floral bouquets when they bloom. It is native to Mexico, and is a plant that requires good sunlight. Dahlias have beautiful flowers with pink, yellow, orange, red, purple or purple colored petals. These flowers are highly sought after at florists, nursery and agricultural supply stores.
This plant is native to Mexico, where between 41 and 50 endemic species have been identified, originating in large numbers from the tropical and subtropical regions of the Aztec country, where they have been cultivated for more than two centuries. These plants are cultivated for their beautiful and abundant flowers of various sizes and colors (white, pink, yellow, purple and other colors except blue).
Horticultural technicians from crosses of different species of the genus Dahlia they have given rise to many hybrids with simple, compound flowers and of different sizes and colors. the name of the genus Dahlia, was placed in homage to the botanist Andreas Dahl, who was a student of Linnaeus. They are plants that grow very well in tropical and subtropical regions of Mexico, they are one of the most used flowers for making corsages.
Cultivation and Care
These plants require good lighting, so they have to be grown in places where direct solar radiation reaches them, where the winds are not strong and the soil has abundant organic matter to make them fertile. Dahlias flowers can have several layers of petals, varying from a single layer of petals, through double, triple and even sextuple layers of petals, resulting from different horticultural crosses. Dahlias flowers with the largest number of petals impress with the intensity of their colors, their spectacular shapes and different sizes from 8 centimeters to more than 15 centimeters.
Climate and soil for cultivation
It is suggested to sow on a well-fertilized soil or on a light compost so that the seedlings take root easily. They are plants that adapt to any type of soil, including calcareous soils with a pH greater than 7. They must be grown in full sun and watered frequently. Wild or pure species are propagated by seeds. Some characteristics for its cultivation are listed:
- Recommended temperature. It is recommended to grow Dahlias at a temperature between 18 °C and 23 °C, these plants are not very resistant to low temperature ranges.
- Light requirement. They adapt to places with good sunlight radiation, likewise, they grow well in places with a little shade where sunlight reaches indirectly.
- Humidity. It requires an environmental humidity between 75 to 78%.
- Planting substrate. Fertile soils with a high amount of organic matter rich in minerals that provide a good amount of macro elements and micro elements, with a loamy texture, permeable that allows good water drainage and a pH between the ranges between 6 and 8.
- Irrigation. Irrigation is applied depending on the stage of the crop. At the beginning of the crop, irrigation must be moderate so that the soil remains moist, without having to become flooded. When the first flower buds grow, irrigation is suggested to increase in frequency and especially in the summer season.
The techniques to cultivate them
The cultivation of Dahlias plants is conditioned according to the function that the planting of their crop will have. Dahlias plants are cultivated for different functions or ways of marketing: such as the production of tubers (cultivation from cuttings), cut flowers and for growing potted plants.
Cultivation by cuttings
For the cultivation of Dahlias from medium sized stem cuttings, cuttings cut during the winter are used and then the Dahlias are started in early summer. If the objective is to plant between 240 to 300 cuttings per square meter, the following steps are carried out: The cultivation of Dahlias from cuttings or by tubers, they must be planted in a medium for rooting, planted in rows separated at a distance 7 to 8 centimeters. The separation between the cuttings is suggested to be between 4 to 5 centimeters and the planting depth of the cuttings must be 1/3 of their length.
The cuttings begin to root when they change color from pale green to deep green and the terminal bud grows. When the roots start to grow and are sufficiently developed, these cuttings are transplanted into furrows and the size of the plantation varies between 0,5 to 1 meter depending on the Dahlia variety.
Cultivation from tubers
The planting of Dahlias tubers begins together with the beginning of spring. On the other hand, if the planting are tubers in vegetation, it will be done in the middle of the spring season. The planting distance is conditioned by the size of the Dahlias flowers. When they are varieties with large flowers, the plantation grid must be 1×1 meter, unlike the tubers for the cultivation of Dahlias with small flowers, it must be 0,5 x 0,5 meters .
The soil to plant the tubers must have a neutral pH and not calcareous, conditioned with decomposing manure to provide organic matter. For its fertilization, it is suggested to apply a dose of 100 kg/ha of P for one hectare of planting.2O5 and 200 kg/ha of K2Or when preparing the soil for planting the tubers and for fertilization or maintenance fertilization, apply 50 kg/ha of N2, in the summer months.
It is advisable to avoid exceeding the dose of Nitrogen because the leaves can increase in size or produce more leaves and affect the aesthetics of the plants. Irrigation of Dahlias crops by tubers is suggested to be abundant and frequent, so that the substrate is always moist and, likewise, without flooding.
Culture for cut flower
The cultivation of Dahlias to produce plants for cut flowers is carried out by planting the stakes or seeds in furrows with a depth between 25 and 30 centimeters, the planting distance between each plant can be between 0,5 to 0,7 this reaches to be different according to the variety that is being cultivated, the conditions of the soil, the agro-cultural practices and other variants.
With the aim of achieving a main flower, pinching is carried out, this practice is carried out on stems of juvenile plants that have a height of about 15 to 20 centimeters. It has to be done above the third pair of leaves from the base. For pinching, flower buds and secondary buds located in the axils of the leaves are removed, leaving only the main bud. This work has to be done before the main shoot reaches 5 centimeters in length. The desired result is to obtain a primary flower whose stem measures between 60 to 70 centimeters.
Soil, fertilization and irrigation
When Dahlias plants are grown to obtain cut flowers, it is suggested to plant them in loose soils, with good porosity and aeration. Similarly, the soil must be well permeable to allow the infiltration of water through the different layers of the soil and thus allow deep layers to retain moisture. It has to be weeding frequently to avoid competition for nutrients, light and water.
It is suggested in fertilization to apply N, P and K fertilizers (nitrogen, phosphorus and potassium), in balanced formulas of 2-1-2 and 1-2-3. As for irrigation, you have to start watering to finish the plantation, if the crop was carried out from tubers or rooted cuttings. The application of irrigation must be planned so that it is constant and in this way control that there are sudden changes in humidity in the soil, in order to ensure that the soil remains moist and benefits the development of the roots.
flower cut
To make the cut of Dahlias cultivated for cut flowers, the beginning of their flowering must be taken into account, which takes place between 60 to 70 days from the date of planting the tubers and lasts for a period of 45 to 50 days. During this period of time, the flowers are cut as they bloom and open. The harvest of these cut flowers takes place every day. This harvest is done when each flower has completely opened and the stem reaches the appropriate size. This determines the commercial classification of Dahlias flowers.
In the ninth month of the plantation, depending on the Dalia variety and how the crop is, the indicated material to produce cuttings begins to be selected and extracted, as well as the mechanical extraction of the tubers. Once the material that is then marketed for the propagation of Dahlias is selected and extracted, it is cleaned and stored at a temperature of between 5 to 10 °C, they must be preserved at a relative humidity of about 80 to 85% so that the tubers keep their weight from when they were removed. The commercial weight of the tubers to produce large Dahlias has to be 40 grams and for small Dahlias 25 grams.
Cultivation of Dahlias in pots
It is suggested that if you want to grow Dahlias in pots to use: Dwarf Dahlias species obtained from seeds and also to use tubers of Dahlias varieties obtained vegetatively in which growth inhibitors were used with the aim of producing Dahlias of small size.
Species of Dahlias obtained from seeds. They require a period of 8 to 12 weeks from sowing for the plants to flower. In the seasons of the year in which it is best to cultivate, it is between the winter seasons and the middle of the spring season, with an average temperature of 18 to 20 °C. Dahlias plants do not tolerate temperatures below 9 °C. On the other hand, Dahlias plants reproduced from tubers begin their flowering stage from the 6th week. They are grown in pots of 20 to 25 centimeters.
The suggested substrate to grow Dahlias plants in pots can be a mixture of previously sterilized soil, peat and perlite in a 1:1:1 ratio. For a good flowering of the Dahlia plant, it is convenient that the peat is rich in potassium, due to the high demand for this element by this plant. Regarding the fertilization or fertilization of plants grown in pots, it is suggested to apply liquid fertilizer at a rate of 100 ppm in a balanced dose of 2: 1: 2 of N, P, K respectively. It should be remembered that Dahlias plants are plants that grow with sufficient sunlight.
Suggestions for growing Dahlias
To ensure that Dahlias plants develop larger and more beautiful flowers, it is suggested to prune the lateral buds, taking care to keep the central bud, which is the highest, in good condition. Do not worry if the first few days do not develop many flowers, however, the new flowers that it will give will be of great size and splendor. It is convenient to remove faded flowers to encourage new flowers to grow.
It is suggested that the place of planting be in gardens and avoid growing Dahlias in pots, since the plant can grow up to more or less a meter in height, due to this the roots require deep soil to fully develop. Instead of planting the Dalia in a pot, the growth of the root system is restricted. Also, Dahlias grown indoors flower less and look less lively.
The irrigation requirements of Dahlias plants are lower during the months that the plant is growing vegetatively, so the frequency of irrigation must be moderate. Increased the frequency of irrigation during the flowering stage, always taking care not to flood the soil to prevent the roots from rotting or being affected by fungi and bacteria.
Dahlias plants can be planted from seeds, cuttings, or cuttings and tubers. For its propagation it can also be by dividing the tubers, by seeds and cuttings or grafts. Sowing is best done between the months of March to May, it is recommended to use vegetable humus and sand to improve the permeability of the soil. The planting depth has to be between 10 to 13 centimeters. Once planted, it is suggested to hold a tutor to give it direction and inclination.
The temperature must be taken into account, since Dahlias plants can withstand up to 5 °C, therefore, Dahlias plants must be protected during the winter season. During propagation and cultivation from tubers it is suggested to remove the tubers after the first frost has passed and protect them in a dry, shady spot protected from light until the spring season arrives.
its spread
Its propagation can be carried out through seeds, cuttings or cuttings, by dividing its tubers and also by tissue culture (vitro). Hybrid species are propagated by dividing tubers, which must be divided so that each division has two dormant buds. This method is the most effective and used to propagate Dahlias hybrids. Wild species of Dahlias can be propagated by seed.
Propagation by seeds
This propagation method is used by horticultural technicians or breeder growers who carry out crosses and thus obtain new varieties. This technique is applied to plants grown in pots. They are sown in the spring season, their cultivation is carried out in pots with vegetable substrate that is mixed with sand, the plants that are propagating require an average temperature of 15 to 18°C. Plants propagated under these conditions germinate in approximately 15 days.
When the two true leaves emerge on Dahlias seedlings, they are transplanted into a larger pot and grown on a 5 x 5 centimeter planting grid. The small Dahlias plants are left in this container until the fourth leaf is born and, when this happens, the plants are transferred again, in this case, to individual pots. When the spring season is ending, the small Dahlias plants are definitively transplanted to the seedling plot, with a distance between plants of 80 centimeters between plants.
Propagation by stakes or cuttings
To carry out this propagation technique, tubers collected the previous year are used and are obtained from the mother plants and, from the moment of collection until the moment they are used for propagation, they must have been kept in a place with low temperature. At the end of the winter season, the tubers are taken and cultivated. Their cultivation to propagate them has to be carried out on hot beds at a temperature of 15 to 20°C and the culture medium is made up of peat and sand mixed at a ratio of 1:1, the tubers are planted leaving only the neck of these at Discover.
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After a few days when observing the emerged shoots and these reached a height of between 5 to 10 centimeters, it is convenient to separate them from the mother plant. This division must be made with a disinfected knife and a clean cut is made under the first two leaves. Likewise, a cut can be made leaving a heel, that is, a piece of tubercle.
Then these cuttings are taken to trays or pots at a temperature of 18°C and the culture medium is an enriched peat. It is expected that in about 2 to 3 weeks the cuttings will already produce their roots. Once the cuttings have produced their roots, they are transplanted to the settlement land to be cultivated.
Propagation by division of tubers
In the propagation of Dahlias plants, the easiest propagation to carry out is the one carried out by dividing the tubers. Dahlia plants form a number of underground tubers as they grow and mature. Propagation by tuber division uses those preserved from the previous year's plantation. These are crops for propagation in a planting substrate made up of a mixture of peat and sand, and placed in a place with high temperature (between 15 to 20°C).
The tubers are kept in this environment until the vegetative buds of the tubers begin to germinate. When this occurs, the tubers are divided, before making the division it must be observed that each tuber has between two to three vegetative buds, to guarantee its propagation. At the beginning of the spring season, the settlement land is conditioned to carry out the planting of the tubers and, the tubers are divided to immediately plant them. Another way to propagate Dahlias is through cultivation propagation. vitro, from vegetative meristems.
Care for pests and diseases
Dahlias are plants that are very sensitive to pests and diseases, which can be avoided if you pay attention to carrying out good cultural tasks, such as proper irrigation in order to prevent the cultivation soil from flooding and damaging the roots. Also, look for a good place to plant and above all that receives good solar irradiation that helps Dahlias grow healthy. Remember to disinfect the tools, the parts of the plants when they propagate, weed and so on, to prevent the Dahlias from contracting diseases or being attacked by pests, especially aphids.
Aphid (Myzus persicae)
Dahlias plants are attacked by aphids (Myzus persicae), during the months of the autumn and winter seasons, due to the low temperatures. The nymphs and adults of Myzus persicaeWhen attacking the plant, they suck the sap and weaken the Dahlias, causing damage to the leaves that turn yellowish and the plant can die. These aphids, being hosts, are transmitters of viruses and, furthermore, while they feed on the sap of the Dahlias, they secrete honeydew and this favors the appearance of the black fungus.
This pest is better controlled through preventive measures, for this you have to monitor the life cycle of the Myzus persicae, when the population of this aphid drops, biological control measures are quite good, its natural enemies are Adalia bipunctata y Aphidius colemani, these are predators of aphids because they feed on them. However, if the population of aphids is very high, the most effective control is through chemical insecticides.
Red spider
When environmental humidity conditions are low, Dahlias plants can be attacked by the red spider mite (Tetranychus urticae). The spider mite attack can be observed when small yellowish spots are seen, the leaf takes the shape of a pod and the leaf falls off. All these are accompanied by small cobwebs on the underside of the leaf blade. To prevent the attack of the red spider, it is suggested to increase the environmental humidity. As a method of biological control is using the mite Phytoseiulus persimilis, which is a natural predator of the red spider. Chemical control is by means of sulfur-based insecticides.
Trips
Other pests that attack Dahlias plants are Thrips (Frankliniella occidentalis), which are evidenced as white spots on the leaves that have a leaden silver appearance and around them have black specks that are their droppings. For its control, blue sticky traps are used, they are used as preventive measures. Amblyseius swirskii u orius in greenhouses. It is unknown that it is used for chemical control.
beetle larvae
Pests of Dahlias plants are white and wire worms, which are beetle larvae that hatch in the soil. Their populations attack the roots of Dahlias plants, once they damage the roots, it is observed that the leaves take on a yellow appearance and then wither. These worms attack more during the spring and fall seasons. If their population increases a lot, chemical insecticides have to be applied. As a preventive measure, it is suggested to plow the soil and observe if there are any eggs, leaving them uncovered so that the sun's rays reach them directly, since they are sensitive to high temperatures.
Dahlia Diseases
Diseases in Dahlias are caused by fungi, bacteria and viruses, as said before these can be prevented if Dahlias plants are healthy, receive enough nutrients, sunlight, environmental humidity and irrigation. Also, keep your planting areas weeded, remove the soil to aerate the soil and eliminate insect eggs that may be hosts of viruses, and remember to disinfect your tools and supplies.
white coal
Signs of White Coal Disease (Entyloma dahliae) they are round, elliptical or angular spots, which can measure up to one centimeter in diameter, the leaves of Dahlias hybrid plants are observed. When it is being affected by the disease, pale spots are observed at the beginning and when they mature, the spots turn brown.
To control the advance of the White Carbon disease, it is suggested to eliminate the plants that are diseased as a preventive measure. Likewise, it is suggested to expand the cultivation surface of the plantation, in the same way tools such as pruning shears, the planting substrate, must be disinfected. Apply agrochemical products with certified products for the control of the white carbon disease.
Mushrooms (Fusarium. sp)
Dahlias plants diseased by the fungus (Fusarium sp.) begins to be noticed when the senescent leaves change color. In the internal tissues of Dahlias these change to a reddish-brown color, and then the damage spreads to the upper organs of the plant. To prevent it, it is suggested to carry out agro-cultural practices, such as weeding plantations, moderate irrigation, disinfecting tools and utensils, as well as the substrate, among others.
Bacteria
Dahlias plants are very sensitive to the attack of bacteria, a bacterium to which Dahlias plants are very sensitive, is the Erwinia chrysanthemi, These bacteria cause rot in the tubers. If you attack Dahlias of varieties that are very sensitive to this bacterium, it can damage your crop by 80% in the propagation phase in the nursery. The bacteria Agrobacterium tumefaciens It produces tumors in the tubers.
While the bacterium Corynebacteririum fascians, generates galls on the leaves. To avoid attack by any of these bacteria, it is suggested to carry out agro-cultural practices such as: prevent plants from having injuries, keep foliage dry, get rid of affected plants, keep planting and pruning tools and utensils clean.
virus attacks
Dahlia plantations may have plants infected by viruses such as Cucumber Mosaic Virus or Cucumber Mosaic Cucumovirus (CMV), and Dahlia Mosaic Virus or Dahlia Mosaic Caulimovirus (DMV), both viruses are transmitted by aphids. CMV causes an interneval mosaic in Dahlia plants.
The symptoms produced by the "Dahlia mosaic virus" are different depending on the cultivar that has infected. Among the symptoms that can be observed are: a change in the pigments of the veins, dark green and also loss of bright yellow pigmentation. It affects the forms of the leaves, appearing leaves of irregular shapes, not symmetrical and curling is produced. In some plants the growth between the nodes is less and the plants take on a dwarf appearance. To eliminate viruses, the population of aphids must be reduced and diseased plants must be eliminated, tools disinfected and other phytosanitary practices.
National Flower of Mexico
Dahlias are plants native to Mexico, identified within the genus Dalhia of the botanical family Asteraceae (Compositae) Tribe Heliantheae, its Aztec name is Acocoxóchitl, which means "aquatic tube flower". Due to their beautiful flowers, Dahlias are plants highly appreciated by Mexican culture, due to this, on October 12, 1995, the Mexican Dahlia Association or Acocoxóchitl AC was organized and in 2007, the National Dahlia Day was created. by the Directive Committee of the Society of the Mexican Dahlias Society.
This plant has a sugary substance that was used medicinally by the ancient inhabitants of Mexico to heal epileptic patients. It should be noted that in recent research carried out by scientists they determined that the sugary substance found in the tubers is suggested to treat the ailments of diabetes.
The commercialization of Dalias flowers is an international business, which according to data provided for the Netherlands, its commercialization yields profits of about 50 million dollars per year. Therefore it is the second export flower after the Tulip which is a flower much loved by the Dutch.
President Adolfo López Mateos on May 13, 1963, issued a decree declaring the Dalia as representative of the National Floriculture, according to the following considerations:
- The Republic of Mexico has a wide diversity of native flowers with great ornamental, floristic and economic value, highlighting the Dahlia flower.
- Due to their great beauty, Mexican flowers, due to their particular characteristics, have obtained recognition both in the Mexican nation and abroad, and especially the Dahlia flowers.
- As a result of the admiration of the Mexicans for the Dahlias flower, it was a reason for one of the species to be recognized with the name of Dahlia Juárez, in homage to the Benemérito de las Américas, Don Benito Juárez.
Likewise, the Dahlia has also been proposed to receive the distinction of national flower by private and public institutions, such as: The Botanical Society of Mexico, the Excelsior newspaper and the National Confederation of Floriculturists and Nurserymen of the Mexican Republic.
According to data provided by the Mexican Dahlia Association or Acocoxochitl, AC (AMD), the Dahlia plant is cultivated primarily in the Mexican states of Mexico City, Tlaxcala, Nuevo León, Puebla and the State of Mexico. Pointing out that this plant has the characteristic of forming roots in the form of sweet potatoes, which can be eaten and have medicinal properties.
Currently Dahlias are cultivated in the fields of Mexico to obtain plants from which infusions are produced from pieces of Dahlia tubers, which are in demand for consumption by diabetics. The flowers of Dahlias plants have the shape of chapters, with a large number of petals that in some species and varieties can reach more than 500 per flower, and with sizes that vary between 6 to 30 centimeters in diameter, of many different colors. and even some of two colors except for the colors blue and green.
Since August 4, 2007, the national day of the Dahlia is celebrated in Mexico, the AMD highlighted the admiration for the extraordinary beauty of the Dahlia flowers, it was recognized by Mexico by growers and the different societies since the time of Netzahualcóyotl and Moctezuma , who ordered that they be collected and planted in the gardens of Tezcutzingo and Oaxtepec.
When the Spanish conquerors discovered Dahlias, they fell in love with their beauty and brought seeds, tubers and plants to Europe in the late XNUMXth century and, in addition to its beautiful flowers, this plant raised interest for its medicinal and food properties. However, the beauty of its flowers and its varieties was very well received by Europeans and they began to be cultivated throughout the continent, the main producers being the gardens of Spain, France, England, Holland, Belgium and Switzerland.
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