Dahlia bloemen aquarel van Bloemoloog.nl

Collection: Organic dahlias

Organically Grown Dahlia Tubers

Dahlias come in various sizes, ranging from small flowers to extremely large blooms. They exist in many different colors, and some even have multicolored petals. The herbaceous leaves vary from light green to very dark green and completely wither after flowering.

Dahlias produce beautiful flowers and bloom extensively from summer deep into autumn, usually until the first frost. Dahlias are perennial if lifted from the ground before frost and replanted after the frost.

Our dahlia tubers are cultivated without the use of chemicals or synthetic fertilizers. Enjoy the power of nature!

Types of Dahlias

The most remarkable feature of dahlias is their diversity. Below is a list of types known to Bloemoloog:

  • Anemone-flowered: Resembles an anemone with a clearly visible central disk.
  • Ball-shaped: The outer curled petals curl so far back that the flower appears round.
  • Cactus: The numerous petals have pointed curled ends, giving the flower a cactus-like appearance.
  • Decorative: A standard type with medium-wide petals, ranging from small to large-flowered.
  • Dinnerplate: LARGE-flowered.
  • Single-flowered: A flower formed by a single or multiple rings of petals around an open heart.
  • Fimbriata: Many narrow petals with fine fringed incisions, ranging from medium to large-flowered.
  • Collarette: A flower with an open heart, surrounded by a collar of narrow, upright petals and a ring of regular petals on the outside.
  • Orchid (star-shaped): A flower shaped like a star, formed by a few single petals.
  • Peony-flowered: Open-hearted dahlias with one or two rings of petals.
  • Pompon: Small round flowers formed by rolled-up petals.
  • Semi-cactus - The numerous petals have pointed curled ends, giving the flower a cactus-like appearance, but the flower is fuller than with the cactus type.
  • Star-shaped (orchid): A flower shaped like a star, formed by a few single petals.
  • Waterlily: A standard type with medium-wide petals, with the outer petals growing slightly less backward than the 'decorative' type.

Planting Dahlias

Dahlias can be started indoors from March or kept until mid-May, after the frost. Dahlias thrive in well-draining soil and prefer a sunny location.

Dahlia Bulbs or Tubers?

A dahlia plant grows from a tuber, which is a thickened, fleshy rootstock whose shape and size can vary depending on the type and age of the dahlia.

Where to buy Organic Dahlias

Good news! Dark-leaved dahlia tubers can now be ordered on bloemoloog.nl due to a recently certified organic dahlia nursery.

Dahlia tubers are available at our markets throughout the season, and you can buy dahlias directly online; orders will be shipped from that March.

Estimated Shipping Widget will be displayed here! (with custom color)


  • On this page you will find our organically grown summer flowering bulbs. In summer, the tubers and rhizomes of perennials mainly bloom. Dahlias have tubers but are categorized as flower bulbs.


    Perennials have a life cycle of several years. They survive the winter period by letting their above-ground parts die and storing energy in their roots or tubers. They will emerge again in the next growing season.

    Numerous varieties of perennials are available, varying in size, shape, bloom time, flower color and leaf texture. This allows you to select a wide variety of plants to meet your specific gardening needs and preferences.

    Care of perennials

    In general, perennials are relatively easy to maintain. They usually require regular watering, fertilization and pruning. However, some species may have more specific care requirements.

    Perennials often have different seasonal characteristics. For example, some perennials bloom in the spring, while others bloom in the summer or fall. This means that with the right selection of perennials you can have a colorful and blooming garden throughout the growing season.


    Because perennials last for several years, they contribute to the sustainability of a garden. They reduce the need for annual replanting, which is both cost effective and environmentally friendly.

    Perennials can also help improve soil quality. Their root systems help retain moisture, prevent erosion and enrich the soil with organic matter as they die and decompose.


    A tuber is a thickened, underground stem or rhizome that stores nutrients and reserve energy. It is a compact mass consisting of the base of the stem and/or the roots of the plant.

    Tubers accumulate reserves during the growing season, mainly through photosynthesis, and then use these reserves to survive in the winter. They act as an energy source for new growth when conditions are favorable again.

    Tubers have a characteristic structure. They are usually round or oval in shape and vary in size depending on the plant species. The outer layer of the tuber, called the husk, can have different textures and colors. The inner part contains the stored starch and other nutrients.

    There are many flower plants that use tubers as a storage structure. Some well-known examples are dahlia tubers, calla tubers, gladiolus tubers and tuberous lilies such as the Madonna lily. These plants usually grow from the tuber and produce flowers, making them favorites in gardens and borders.

    When is the best time to plant tubers?

    Some tubers such as gladiolus and freesias are perennial, but not winter hardy. You only plant this in the ground after the last night frost. It is best to take the middle of May into account, because after the ice saints the chance of night frost is very small.

    It is important to remember that flower tubers thrive best when soil temperatures are optimal. In general, a soil temperature of about 10-15°C is ideal for most tubers. You can check the soil temperature using a soil thermometer.

    Favoring indoors

    You can also choose to grow the tubers indoors from March onwards, which is what we call pre-cultivation. Then the plant has an advantage and blooms earlier. You then place the pot in a bright place in your room and keep the soil slightly moist. As soon as the night frost has passed, the pot can be placed outside or the tuber can be removed and replanted in the ground. In that case, first keep the pot in a bucket of water for half a day and then plant the tuber in the open ground.

    Care of tuber plants

    Tubers can be cared for and propagated relatively easily. They should be planted in well-drained soil and usually require a sunny position. During the growing period they must be regularly watered and fertilized. After flowering, the tubers can be dug up, dried and stored until the next growing season.

    Some tubers can be propagated by dividing them into pieces or by planting so-called 'tubers', small tubers that form around the main tuber.

  • There are many different types of summer flowering plants, including annual and perennial plants, also called perennials. Annual summer bloomers are plants that bloom for only one season, while perennial summer bloomers grow and bloom for several years. One must be removed from the ground before the cold winter and the other, with the right care, can remain in the same place for years.

    When choosing summer bloomers, it is important to take into account the specific needs of the plants, such as water requirements, soil type and care.

    Below we discuss some popular summer bloomers and provide information about which location is best for them.

    Non-hardy perennial summer bloomers

    - Calla: Calla's also known as Zantedeschia's are summer bloomers with graceful leaves and unique flowers. These can be grown in the sun and partial shade.
    - Dahlia: Dahlias are a popular choice for summer bloomers and come in many different colors. They do well in full sun.
    - Gladiolus: Gladiolus are perennial, but not winter hardy. These grow best in full sun.

    Winter-hardy perennial summer bloomers

    - Kniphofia: Kniphofia, also known as fire arrow, likes a lot of sunlight. Place the plant in a location where it will receive at least 6 to 8 hours of direct sunlight per day. A sunny position ensures that the plant grows and blooms well.
    - Lily: Lilies are perennial summer bloomers that are often planted. These plants do well in full sun and partial shade.
    - Peony: Peonies are well-known perennial summer bloomers. They bloom in the sun, but for longer flowering we recommend a partial shade spot.

    Native summer bloomers

    Native plants are plants that occur naturally in a particular region or area. They are adapted to local conditions, including the climate, soil type and biodiversity of the region. Choosing native summer flowering plants has several benefits, such as supporting native flora and fauna, promoting biodiversity and facilitating gardening with plants that are well adapted to local conditions.

    Some examples of native plants from the Florologist's range include the Allium 'Schoenoprasum' (Temporarily unavailable), also known as chives, and the Liatris, also called splendid scissors or lamp polisher.

    More care tips can be found in the products themselves. Take a look at our organic summer bloomers. Hopefully there is something nice for you.

    Available to order now

    Organic summer bloomers

    Delivery from the beginning of March!

1 of 2