Dahlias Growing: How Long do Dahlias Bloom?

Have ever seen dahlias flower, I can bet you will fall in love with them at first sight as I do. Must be thinking why I am praising these flowers. What are they? How do they look?

Put a full stop to your questions because you have come to the right page, here I have explained everything about the dahlia flowers so that you can also grow them in your garden. Even if you are a beginner this guide will make you a pro in planting dahlias flower. Start reading this article and get answers to all your questions.

About Dahlias 

The dahlias belong to the Asteraceae family. The other flowers that belong to this family are daisies, sunflowers, and chrysanthemums. The dahlias used to grow as perennial plants but in case if you are living in the cold winter season you should grow the dahlias as annual plants. 

The flowers are native to Central and South America. these plants are used as traditional medicine by Aztecs and many others. The dahlias in 1963 were also declared as Mexico’s national flower. The plants do come in many groups and varieties and you can select from them. Growing them as your houseplants will make you enthralled with color combinations and diverse shapes. 

Dahlias Growing: How Long do Dahlias Bloom?

Some basic about dahlias:

Zones:Treated an annual in USDA zones 3 through 7, overwinters and returns as a perennial in zones 8 through 11.
Height/Spread:Depending on variety or cultivar, ranges from 1 foot to 6 feet tall and 1 foot to 4 feet wide.
Exposure:Full sun, with partial shade acceptable in the afternoon or in hot climates.
Bloom Time:Most dahlia varieties bloom in late summer and continue until killing frost, each flower lasting between two and five days.
Colors:Orange, pink, red, white, black, burgundy, salmon, purple, light green, cream, yellow, and multi-colored.
Types:Pom pom, mignonette, anemone, collarette, dinner plate, decorative, cactus, tree, peony-flowered, dwarf, border and bedding, ball and miniature ball, waterlily, and single-flowered.

How long do dahlias bloom? 

After planting dahlias you need to wait for approximately 8 weeks to see them blooming. Most common dahlias that are planted first start to open their petals in mid-July.

For blooming the dahlias do take around 120 days as they start blooming in mid-July and complete the beautiful blooms in mid-November. The dahlias are interesting plants that will bring color to your garden after the other flower dies. 

Planting Dahlias:

You can grow dahlias from the tuberous roots instead of growing them from the seeds. They used to have bulbs and flowers that were planted from root cuttings, containing tubers like potatoes or ginger. You need to plant them at the right time of year as dahlias are more sensitive and have a chance of freezing damage. 

Growing the dahlias by direct seeding grows too slowly. You need to start seeding 8 to 12 weeks before the first date so that they get the perfect time to grow properly. Remember to plant them at the right time so that there is no failure in growing them. 

When to Plant Dahlias: 

You can plant the dahlias after the timer of late frost is gone and the temperature of the soil is warmed up to 60 degrees because if the planting is done in late frost that will kill the tubers and all your efforts and money will get wasted. 

So to plant them you can plant them after a few weeks rather than planting too early. Planting of dahlias in warm climates in USDA zone 8 can be planted in the fall. You can also plant them in the fall only when the frost date is after May 1st and plant the roots in pots a month before so that they get time to grow. 

Where to Plant:

For a perfect location for keeping the plant, you need to find a place where they get full sun and plenty of moisture. Also, the area should be protected from wind and direct sunlight, especially in the afternoon. 

I will suggest you keep them in south and eastern exposure where they will get plenty of light but you need to protect them from the afternoon sun because it will bake the soil and the roots of the plant will dry. You can also plant the dahlias against the wall in order to increase warmth and reflected light. 

Dahlias Growing: How Long do Dahlias Bloom?

Dahlia Flower Varieties:

The dahlias flower are divided into 14 different groups according to royal horticulture society such as:

  • Group 1 – Single-flowered dahlias (Sin)
  • Group 2 – Anemone-flowered dahlias (Anem)
  • Group 3 – Collarette dahlias (Col)
  • Group 4 – Waterlily dahlias (WL)
  • Group 5 – Decorative dahlias (D)
  • Group 6 – Ball dahlias (Ba)
  • Group 7 – Pompon dahlias (Pom)
  • Group 8 – Cactus-flowered dahlias (C)
  • Group 9 – Semi cactus dahlias (S–c)
  • Group 10 – Miscellaneous dahlias (Misc)
  • Group 11 – Fimbriated dahlias (Fim)
  • Group 12 – Single Orchid (Star) dahlias (SinO)
  • Group 13 – Double Orchid dahlias (DblO)
  • Group 14 – Peony-flowered dahlias (P)
Dahlias Growing: How Long do Dahlias Bloom?

According to the New Zealand society, the dahlias flower is divided into different varieties as per their blooming diameters such as:

  • Giant-flowered cultivars: over 250 mm.
  • Large-flowered cultivars: 200–250 mm.
  • Medium-flowered cultivars: 155–350 mm. Small-flowered cultivars: 115–155 mm.
  • Miniature-flowered cultivars: 50–115 mm.
  • Pompom-flowered cultivars: less than 50 mm.

Factors Affecting Dahlia Plant Growth

The following are different factors affecting dahlias plant growth such as:


In case the soil is not a good draining soil then it is a big problem for the dahlias growth. If the soil is heavy clay the flower will grow slowly and fail to grow flowers. Not the loose sand will help them to grow as the soil will drain too quickly and the plant will try out soon. So to plant the flower in perfect soil we need to mix plenty of organic material. 

Amendments & Fertilizer: 

For adding nutrients you can add Compost, peat moss or sphagnum moss and aged manure and loosen out the soil. You can mix dahlia fertilizer into the soil before planting them.


If the plants are provided with uneven watering that will slow down the process of growth and flowering so you need to keep the water levels equal and maintain the schedule of watering the plants. Make sure the soil does get dry out more than a few inches.

Dahlias Growing: How Long do Dahlias Bloom?

Diseases and Pests: 

The dahlias flowers are able to attract thrips, aphids, mites, and mealybugs. They can get infected with fungal diseases and rots. You need to keep the moisture levels of the soil from getting too high. In case to protect the plant from frost, disease, and pests you can use organic pesticides.

Other Factors: 

The Dahlias plants are sensitive to low night-time temperatures. In case to protect the plants from summertime dip you can keep the plants in pots so that the flowers grow on a chilly night.


Hence the time taken to bloom dahlias is around 2 months but you need to have patience for growing them. Until then you need to take proper care of the plant by providing them weekly water and monthly fertilizer. 

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