How to grow dahlias

Dahlias are beautiful flowers that bloom from mid-summer to autumn. A wide range of varieties is presented, there are even dwarf ones with single or double flowers. They are available in a variety of colors (from white to dark red and two-tone), flower shapes and sizes.

About dahlia flowers

Dahlias are a genus of tuberous plants belonging to the Compositae family. There are about 60,000 named varieties and 18 official flower forms. Dahlias came to us from Central America.

They are perennials and are often grown as annual flowers in many regions. In recent years, the number of varieties has increased significantly and a greater number of colors and forms of flowers. Dahlia flowers come in the most unusual colors and shapes, and their sizes can vary from 3 to 25 cm.

Additional Information! The flower heads consist of numerous individual tubular flowers and are surrounded by petals. They make beautiful cut bouquets, and many people only grow them for cutting. The more dahlias are cut, the more they will bloom!

The height of different varieties varies: from 30 cm to two meters in height. They will brighten up any garden and can be used as a border plant or as a background plant. Medium and dwarf dahlias do great in containers.

Tubers are planted in the ground in late spring. Dahlias have a long flowering period, and usually bloom from July until the first autumn frosts.

Caring for dahlias in the garden

They are relatively easy to grow. They love humid, temperate climates and full sun, but are not well suited to hot climates. They need protection from the wind.


This is a very water demanding plant. It must be watered during the period of growth and flowering. With frequent watering, as well as in rainy summers, there is a danger of tubers rotting.

Top dressing

The plant is more demanding on nutrients. To obtain beautiful and large flowers, a mature organic fertilizer or compost should be applied before planting.

Important! From the moment of emergence of seedlings, fertilizers with a low nitrogen content are applied. An excess of nitrogen causes the growth of green mass at the expense of flowering.

Fertilize every 3-4 weeks in the middle of summer and until the beginning of autumn. Fertilizers should be applied only after abundant watering. Dahlias respond very well to feeding with wood ash.

When to plant dahlias

Tubers purchased or harvested in autumn are planted from the second half of April. Dahlias do not tolerate cold soil, they are planted when the ground temperature reaches 15°C. Choose a sunny, well-lit place.


They grow best in rich, well-drained soil with a pH of 6.0 to 7.5. Heavy clay soil is improved with old manure or compost to loosen the texture and improve drainage. It is important that the soil is not hard, and the roots can penetrate well into it. Wet places are not suitable for dahlias.

How to plant dahlias

Caring for dahlias in the garden

Tall dahlias are planted in a specially designated area where they will not interfere with other plants. Sufficient distance must be maintained to all neighboring plants.

You can combine different types of dahlias. This creates a colorful picture that draws attention in every garden.

 Various varieties

Sufficient distance must be maintained to all neighboring plants. The larger the plants, the wider the planting distance.

  • Dahlias high and medium height are placed at a distance of 60 cm from each other.
  • The smallest dahlias grown from seeds are planted at a distance of 30 cm from each other.

Prepare holes with a depth of 20 cm. Planting depth depends on the size of the bulb. Add some compost or manure to the planting hole Dahlia tubers should be just below the ground. They are covered a few centimeters with loose sandy soil so that seedlings can easily germinate.

Note! If you are planting a high variety of dahlias, you should think about a support. The flowers may be too heavy and the stems will break off.

“Eyes” or some greenery indicate the good condition of the tubers. Place the tubers in the hole with the sprouts up.

Immediately after planting, the tubers are not watered, as this contributes to rotting. When the sprouts appear above the ground, they begin to water. When dahlias take root, water 2-3 times a week in the heat. The soil is not mulched, as the mulch covers the roots from the sun. Weeds are removed by hand so as not to accidentally cut the tubers with a hoe, and the stem will die.

When the plants reach a height of about 30 cm, pinch the central branch up to 10 cm to stimulate bushiness. Later, in the process of growth, side shoots appear that need to be removed. Several shoots are formed from one stem, and if all of them are left, you will get a dense plant with a large number of small flowers.

Storage of dahlia tubers in winter

As the days get shorter, the plant begins to store more nutrients in the tubers. The later they are taken out of the ground, the stronger they will be next year. When the stems are affected by the cold, the tubers are taken out of the ground for storage. Cut off the stem above the ground, carefully dig out the root with a garden fork or shovel, avoiding damage to them. Shake off the remaining earth, dry in the sun for several days.

 Storage of tubers in winter

Store planting material in a well-ventilated cool room. The ideal temperature is between 5 and 8 °C. If the temperature is too high, the tubers may lose too much water and not germinate next year. So that they do not dry out, they fall asleep with sawdust or dry sand. Check the tubers during the winter, removing those that have begun to rot so that the rot does not spread to healthy ones.

Plant propagation

Dahlias can be propagated in several ways. The easiest way to propagate dahlias is by dividing the tubers. New shoots are formed at the transition point between the tuber and the stem of the plant. Here you can carefully divide the tuberous root, and get new plants.

 Planting material

Varieties with a height of 40-60 cm are sold as tubers, but they can also be propagated by seeds, as annuals. To collect seeds from your own dahlia, leave 1-2 flowers to form seeds, cut the rest after flowering. This is important because the formation of seeds takes a lot of energy from plants, which can adversely affect subsequent flowering.

In the spring, healthy tubers are separated from the parent lump and discarded when shriveled or rotten. Each tuber must have at least one “eye” or part of the stem, otherwise they will not develop. Dahlia buds are located at the base of the stem part connected to the tuber.

Diseases and pests

If the plant is weak and hardly blooms, then the soil is poor in nutrients or waterlogged, or there is not enough sunlight.

Aphids often attack dahlias, so they are regularly checked. The problem can be easily eliminated if it is noticed in time. If the pests have already appeared on the plants, the following solution can be used against them:

  • 0.5 liters of water;
  • 2 tbsp. l. Sahara;
  • 2 tbsp. l 10% vinegar;
  • 2 tbsp. l dishwashing liquid.

For several days, spray the affected plants with the mixture twice a day. After use, the leaves will probably fall off, but this is only a temporary condition. After the pests disappear and the spray is not used, the plant will quickly recover.

The big enemy of dahlias are snails and slugs. They are harder to deal with. You can create natural barriers around sawdust, lime, bark, or coffee grounds. Slugs do not like fragrant plants. Densely planted, they are a barrier to snails.

 Dahlia diseases

Dahlia leaves may be covered with yellow-green or brownish spots. Remove infected leaves immediately. This disease occurs due to too humid environment.

In general, dahlias are resistant to disease and are not damaged by insects, and are currently one of the most diverse garden flowers.