Dahlia 'Hartenaas' – Collarette Dahlia

Start tubers indoors in pots from early April to get a head start, then plant out in late May once all danger of frost has passed. Choose a sunny or lightly shaded spot with rich, well-drained soil and set each tuber 5–7 cm deep with the eyes facing upward. At its compact 50–60 cm height, 'Hartenaas' rarely needs staking, making it refreshingly low-maintenance for a dahlia. Pinch out the growing tips of young plants to encourage branching and more flowers. Deadhead regularly to keep blooms coming. In the Baltic climate, dahlias will not survive winter in the ground: lift the tubers after the first frost blackens the foliage, let them dry, and store in a cool, frost-free place until spring. Thrives in large containers on a sunny balcony or terrace.

The open, single-petalled form of collarette dahlias gives bees and butterflies easy access to the nectar and pollen in the golden centre — one of the most pollinator-friendly dahlias you can grow. For the vase, cut in the cool of the morning when flowers are three-quarters open; plunge stems straight into deep cold water and expect 5–7 days of vase life. The sugary pink and white tones pair beautifully with blue delphiniums, white cosmos, and purple heuchera foliage in romantic summer bouquets.