Once upon a time, dahlias were considered one of the most beautiful flowers to display during the Tet holiday, “with gladiolus being the first and dahlias the second.” Below is an expert guide by Nguyen Lan Hung on how to grow dahlias to bloom just in time for Tet.
How to Grow Dahlias
Dahlias (Dahlia Variablis Desh) originate from Mexico and have been widely cultivated in Vietnam, especially in regions like Da Lat, Hanoi, and Hung Yen…
Dahlias are a familiar flower for many generations of Vietnamese people. They have been cultivated in Vietnam since the French colonial period and have become a traditional flower for Tet in many regions. Some people believe that if there is no vase of dahlias on the ancestor altar, it does not truly feel like Tet.
Dahlia plants can adapt to various climates, from cold to hot and humid, so the techniques for cultivating dahlias do not require excessive care. Just a little knowledge about suitable weather conditions will yield vibrant, beautiful flowers right in time for Tet.
In recent years, the trend of growing cut dahlias has suddenly surged, along with the emergence of a new hobby—growing potted dahlias.
Here are some notes on planting and caring for potted dahlias to achieve abundant blooms with large, vibrant colors.
How to Grow Dahlias for Tet
Dahlias are flowering plants with a wide variety of colors. Currently, there are two main types of dahlias: single-flower and double-flower dahlias. Single-flower dahlias have thin petals and a single row of petals, which are beautiful but have been less popular for cultivation.
Double-flower dahlias have many beautiful shapes and colors, with multiple layers of petals arranged in various stunning ways. They come in a variety of colors such as flag red, bright red, velvet, goat fur, blood red, orange, brick red, dark lotus, light lotus, creamy white, translucent white, deep yellow, and golden yellow…
The Vegetable Research Institute has recently introduced a new variety of dwarf dahlias. This is great news! This type of flower only grows to a height of 30-40 cm and is already flowering.
Cut dahlias tend to last only 5-7 days, sometimes just 4 days. However, if you grow dwarf dahlias, you can keep them in pots.
In this case, people can display the pots indoors or right on the table. Potted plants can bloom for up to a month.
Dahlias are highly favored during Tet.
Using dwarf dahlias, you will have flowers throughout the Tet holiday. This is a significant advantage of this flower variety.
Potted plants can be placed around the yard, along pathways, by the pond, or even on the terrace. You can care for them just like those grown in the fields.
How to Care for Dahlias
- Dahlias require a cool climate, with a preferred temperature of 15-30 degrees Celsius. They need high humidity but cannot tolerate waterlogging.
- This flower needs to be fully illuminated, but as it approaches flowering, it requires reduced light and cooler conditions to differentiate flower buds.
- Dahlias bloom early, typically within 50-60 days. Therefore, anyone planning to grow dahlias must calculate to have them in bloom for Tet.
- Care before blooming: remove all buds from the young branches starting from the fifth leaf. Place the pot in a sunny location, and water it after the soil surface has dried.
- After flowering: proceed with pruning, leaving only 2-3 branches to help lateral buds develop so that you can enjoy more blooms in the fall. During the flowering period, fertilize once a month.
- This flower requires full sunlight, but as it nears blooming, it should be placed in conditions with reduced light and cold to differentiate flower buds, hence it should be kept in places that are not dew-prone.
Around April – May, when dahlias stop blooming, cut back the stems.
Dahlias can be propagated by seed, tuber, or cuttings. Cuttings can sprout roots in just 5-7 days if treated with rooting hormones.
Seed propagation is only applicable for single-flower dahlias, while double-flower dahlias are propagated through budding or stem cuttings. Around April – May, when dahlias stop blooming, cut the stems back to 20-30 cm, carefully uproot the plant with the soil ball, keep it in a cool place, or bundle the soil and store it indoors.
In early August, plant the tubers, ensuring not to lose the root section, as the tuber cannot sprout buds without proper care. After 15-20 days, new shoots will emerge from the stem nodes. Every 12-15 days, take sprouted shoots for cuttings. If planted in dry soil, keep the entire plant intact, shade it during the summer.
In July – August, when the plant produces shoots, separate the shoots with 4-6 leaves, ensuring to take a root section for quicker rooting. You can also cut the top of the plant.
Harvesting Tubers: The ideal time is in mid-November. After harvesting the tubers, do not remove the outer soil layer; store them in a place protected from dew.
In the past, people would split the buds into 2-4 sections to promote more roots.
After two pinches from one initial plant, it can produce 9 to 15 cuttings for propagation.
- Preparing the Mother Plant Garden: To cultivate 15-20 hectares of dahlias, you need a 1-hectare garden of mother plants that are of high quality and free from pests and diseases. Besides the flower production standards, the location of the mother plant garden must meet technical requirements such as being high and dry, wind-protected, and conveniently located near transportation for easier handling and storage of seedlings. If possible, a nylon-covered shelter should be constructed to protect against heavy rain, strong winds, and heat.
The selected mother plants should be imported varieties, either from tissue culture or from garden-grown plants that produce many roots, are robust, and pest-free, planted with a spacing of 15 x 15 cm (density of 400,000 plants/ha). After planting, wait 12 to 15 days before pinching the first shoot to encourage branching, and pinch again 20 days later.
After two pinches from one initial plant, it can yield 9 to 15 cuttings that can be taken for propagation. This pinching also encourages branching and budding. Afterward, every 15-20 days, a new batch of shoots can be harvested. Thus, from one plant, you can get up to 50-70 shoots.
With this level of pinching and cutting, within one growing season of 4-6 months, one hectare of mother plants can provide 6-8 million cuttings sufficient for planting 15-20 hectares.
Choose semi-mature cuttings that are neither too old nor too young.
- Preparing the Cutting House: If possible, use fixed greenhouse or net houses with devices to regulate light, wind, temperature, and humidity, as this is the best option. Alternatively, you can design a simple cutting house using inexpensive materials such as bamboo rods bent into an arch shape, with a span of 2.2-2.5 m, height of 1.8-2 m, covered with two layers of nylon to reduce light intensity, lower temperature, and shield against rain and wind while retaining moisture inside.
Choose semi-mature cuttings that are neither too old nor too young, with healthy vigor, a length of 6-8 cm, and 3-4 healthy green leaves, free from pests, for propagation. Thicker cuttings with more leaves should be spaced further apart (3 x 3 cm = 1,000 cuttings/m²); smaller cuttings with fewer leaves should be closer together (2.5 x 2.5 cm = 1,500 cuttings/m²); cuttings should be denser in the fall than in the summer.
- Handling Cuttings: Cut the cuttings in the morning and process them immediately to avoid water loss, as wilting can affect root development. Use growth stimulants like IAA, IBA, or NAA diluted to a concentration of 25 to 50 ppm. Dip the cut ends in the solution for 10 to 15 seconds to encourage rapid rooting.
- Rooting Cuttings: Insert the cut ends 1.5 to 2 cm deep into the soil bed or in specialized plastic trays with clean soil. There are two methods for rooting: dry rooting (placing the cut ends in clean sand and then watering) or wet rooting (moistening the sand thoroughly before inserting the cuttings). The time for cuttings to develop roots varies from 10 to 15 days depending on the weather (15 to 20 days in hot and cold seasons, while only 7 to 10 days in cooler months). Thus, it is essential to schedule the planting season appropriately for optimal cutting propagation.
Regularly water the cuttings by misting to promote quick rooting (in the first few days, mist 3 to 4 times a day, then reduce while ensuring the leaves remain lush). Remove any yellow or old leaves and apply foliar fertilizer once the cuttings have recovered and developed roots for healthy growth. After 12 to 15 days of rooting, each cutting should have 3 to 5 roots measuring 2 to 3 cm long and stable leaves, making them ready for transplanting into the production garden.
Dahlia Flower Care Techniques
When preparing to bud, be sure to place the plants in a dark, cool place to facilitate flowering.
After 7 to 8 days, the seeds will germinate. After 20 to 25 days, transfer the seedlings to new pots for care. Dahlias prefer sunlight, so keep the plants outdoors. However, when preparing to bud, it is important to place them in a dark, cool environment to encourage blooming. Water them every morning and evening to maintain soil moisture and prevent sunburn.
Fertilizers for dahlias mainly consist of well-rotted manure and compost. During the budding process, pay attention to supplementing nutrients to promote beautiful flowers.
Pest and Disease Control: Dahlia flowers are often affected by leaf-eating insects, leaf miners, and various fungi. Leaf spot disease mainly occurs during the rainy season due to humid weather, initially appearing as yellow spots on the leaves, which later expand into round brown spots. In this case, use a 0.1% Zineb solution and 0.5% Bordeaux mixture for spraying.
If the plants experience root rot, the main cause is overwatering, resulting in excessively moist soil. The only way to address this issue is to wash the roots with 60-degree alcohol and then replant.
The Significance of Dahlia Flowers
Meaning in Feng Shui During Tet
- To dissolve obstacles in love.
- To bring luck and success to the whole family.
The Meaning of Flowers in Life
Dahlia flowers typically symbolize:
- Grace under pressure, especially in difficult situations
- Inner strength for success
- Travel and positive life changes
- Standing out from the crowd and following one’s own path
- Kindness even when tested by certain life events
- Seeking a balance between adventure and relaxation
- Commitment to others or a particular ideal
- A warning to someone about the risk of betrayal.
Depending on their colors, dahlias have unique meanings:
Red Dahlias: These symbolize sweet love and lasting happiness. Additionally, red dahlias represent the passion and fervor of youth.
White Dahlias: The color of this flower symbolizes purity, innocence, and the gentleness of a woman.
Yellow Dahlias: They symbolize elegance and prosperity, bringing wealth and fortune to the homeowner. Particularly, yellow dahlias convey the message of “overflowing happiness” aimed at couples.
Purple Dahlias: They symbolize loyalty and steadfastness in marital affection, remaining constant throughout.
Blue Dahlias: They symbolize hope and the best things to come in the future.
Tips for Planting Dahlias to Bloom Right for Tet
The secret to ensuring dahlias bloom in time for Tet is to time the planting and pinching appropriately for each growing method:
Planting with Seedlings requires a growth period of 90 to 100 days, so start planting from mid-September of the lunar calendar, pinching twice at 20 days and 40 days after planting.
If planting from seeds or tubers, the growth period is 110 to 140 days, so you’ll need to plant earlier. Pinching can be done 1 to 2 times depending on the plant’s growth.
How to Arrange Dahlias for Tet
Choosing Flowers
Select beautiful and fresh dahlias. Fresh dahlias should have long, robust stems with a mix of large blooms, buds, young leaves, and mature leaves.
The leaves of the dahlias should be uniformly green, intact, and free from yellowing. The petals should be well-formed, and the stems should be long and firm without any unpleasant odor.
Choosing a vase for dahlias is different from other flowers. A round vase, a cylindrical vase, or a flared vase is recommended for dahlias.
Arranging Flowers
For beginners, it’s best to use floral foam for simplicity and structure. The floral foam for dahlias should be pre-soaked in water.
Once you have the foam, insert 4 dahlia stems into the corners of the foam, ensuring that they anchor well into the main vase’s mouth.
After inserting the 4 flowers, gently lift both the flowers and the foam to transfer them into the main vase. Be careful to avoid damaging the arrangement.
Then, place the foam into the vase’s opening and continue to insert the younger stems and buds around the mouth of the vase.
Finally, insert the remaining dahlia flowers at an angle, balancing them on all sides—front, back, left, and right.
This method of arranging dahlias is not only simple but also visually appealing, making it suitable for beginners or those less experienced in flower arranging.
How to Keep Dahlias Fresh and Sturdy
To keep dahlias fresh and sturdy, pay attention to the following tips:
When buying flowers, do not arrange them immediately. Clean the leaves and stems by placing the entire bouquet in a bucket of water (ensuring the blooms do not submerge) for about 30 minutes.
This method should be applied to any flower purchased to allow them to absorb enough water before arranging. Cleaning the leaves and stems will prevent stem rot and foul odors.
Florists typically just mist the flowers to keep them fresh, but that is not sufficient water. If you skip this step before arranging, the flowers will not look vibrant and fresh.
Add white vinegar to the vase before arranging the flowers: One of the best ways to keep flowers fresh is to add white vinegar to the vase about a minute before arranging.
White vinegar and water act as a catalyst to prevent flowers from wilting after the third day.
Add sugar to the vase: Adding one tablespoon of sugar to the vase will help flowers stay fresh longer as sugar enhances photosynthesis. However, a drawback of this tip is that it encourages bacterial growth. Nevertheless, you can still try this method to keep flowers fresh.
Add a little cooled tea to the vase: This method can help keep flowers fresh for up to 7 days.
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