Dahlias are one of the most popular cut flowers because they produce beautiful and long-lasting inflorescences in a wide range of forms, sizes, and colours. Growing dahlias for cutting, on the other hand, necessitates great care and attention because to their sensitivity to cold, pests, and diseases. We'll walk you through the process of cultivating dahlias for cutting inflorescences, from selecting the correct types to planting and caring for them to harvesting and storing them.
Important takeaways
- Dahlias are classified into 14 groups based on the shape and size of their inflorescences, which range in diameter from 5 cm to 30 cm.
- Dahlias may be produced from tubers or seeds, although tubers produce bigger and more diversified inflorescences.
- Dahlias require a sunny, well-drained position, rich, wet soil, consistent watering and feeding, and protection from frost, snails, and aphids.
- Dahlias should be cut when the inflorescences are fully open, ideally in the morning or evening, and immediately placed in a bucket of water.
Dahlias can be kept in a cold, dark spot for up to a week, or dried for longer storage.
Dahlias are classified into 14 groups based on the shape and size of their inflorescences, which range in diameter from 5 cm to 30 cm. Some of the most common cutting groups are:
**Decorative dahlias**: These feature big, flat petals in the shape of a ball or oval. They are available in a variety of colours and bicolbi-coloursors and are great for adding a splash of colour to bouquets and centrepieces. 'Café au Lait,' 'Thomas Edison,' and 'Arabian Night' are a few examples.
**Cactus and semi-cactus dahlias**: These feature long, pointed petals that curve backwards and forwards, giving them a spiky or star-like look. They are highly visible and give texture and contrast to flower arrangements. 'Chat Noir,' 'Nuit d'Été,' and 'Yellow' are a few instances.
**Ball and pompon dahlias** feature petite, spherical inflorescences that look like pompoms or balls. They are quite consistent and clean, and they are ideal for adding colour and filling gaps in bouquets and arrangements. 'Cornel,' 'Little Robert,' and 'Willo's Violet' are a few examples.
**Anemone-flowered dahlias**: These feature a tubular disc in the centre surrounded by one or more rows of flat ray florets. They have a delicate and whimsical appearance and are ideal for achieving a romantic and feminine impression. 'Totally Tangerine,' 'Blue Bayou,' and 'Honka' are a few examples.
**Single-flowered dahlias** contain a single row of flat ray florets around a centre disc. They are simple and attractive, and they attract bees and butterflies. 'Bishop of Llandaff' is one example.
The table below summarizes the main characteristics of each group:
| Group | Inflorescence size | Inflorescence shape | Petal shape | Petal arrangement |
|---|
| Decorative | 10-30 cm | Ball or oval | Flat | Regular |
| Cactus and semi-cactus | 10-30 cm | Spiky or star-like | Pointed | Curved |
| Ball and pompon | 5-10 cm | Spherical | Round | Regular |
| Anemone-flowered | 5-15 cm | Disc and ray | Tubular and flat | Irregular |
| Single-flowered | 5-15 cm | Disc and ray | Flat | Regular |
Dahlia plantation and care
Dahlias may be produced from tubers or seeds, with tubers producing bigger and more diversified inflorescences. Tubers are available at nurseries and online retailers, and should be planted in the spring, after the last frost, in a sunny, well-drained position. The soil should be rich and wet but not soggy, and it should be supplemented with organic materials like compost or manure. Depending on the size of the variety, the tubers should be planted 10-15 cm deep and 60-90 cm apart. To support the plant as it grows, attach a stake close to each tuber.
Dahlias require consistent watering and feeding throughout the growth season, especially during hot, dry spells. Every two weeks, a balanced fertiliser, such as 10-10-10, can be used, or a slow-release fertiliser can be incorporated into the soil at planting time. Mulching is also beneficial to dahlias since it helps to retain moisture, control weeds, and protect the tubers from cold. Dahlias should be pruned when they reach a height of around 30 cm to stimulate branching and additional inflorescences. Deadheading, or the removal of spent inflorescences, encourages continual flowering and avoids seed production.
Dahlias are vulnerable to cold, snails, and aphids, all of which can harm the plants and inflorescences. When the temperature falls below 5°C, cover the plants with a frost cloth or a covering of straw or leaves to protect them from frost. Slugs can be deterred by placing a barrier of crushed eggshells, diatomaceous earth, or copper tape around the plants, or by using slug bait. A powerful spray of water, a soap solution, or a natural predator such as ladybirds can be used to control aphids.
