Dahlia pinnata
Dahlia
Common names: Dahlia pinnata, Georgine
At a glance
- Light
- Full sun
- Pot size
- from 30 l
- Lifespan
- Perennial
- Hardiness
- Cold damage below 1 °C
- Water need
- High
Photo: W. Bulach · CC BY-SA 4.0 · Source
This description was machine-translated.
Description
The tuberous Dahlia blooms from July until the first frost in a wide range of shapes and colors, making it one of the most reliable cut flowers in the farmer's garden. It grows from overwintered tubers and provides a steady supply of blooms for the vase over many months.
Care instructions
Pre‑treat the tubers in mid‑April in a frost‑free area and plant them after the last frost (mid‑May, week 20) in a sunny spot with nutrient‑rich soil. Water regularly and deeply, especially during heat periods, and consistently remove spent flowers to encourage prolonged blooming. After the first frost in October, dig up the tubers, store them frost‑free and dry for overwintering.
The care notes were machine-translated from German.
Garden year
PlantingApr–May
Soil & site
Soil pH
Soil type
humus-rich, well-drained, nutrient-rich
Dahlias need loose, humus-rich, well-drained soil, because waterlogging makes the tubers rot. Before planting, improve heavy loam soils with mature compost and a little sand; the pH is best slightly acidic, at about 6.5.
Feeding
Heavy feeder
Months
May–Jul
When planting the tubers from mid-May, put mature compost in the planting hole and work horn shavings in shallowly. This carries the plant through the establishment phase. During the growth and flowering period (June to August), top up with organic fertiliser about every three to four weeks. From the end of August, stop feeding so that the tubers ripen and overwinter well.
Overwintering
After the first night frost (the foliage turns black), cut the stems back to about 10 to 15 cm and carefully lift the tubers with a digging fork on a dry day. Shake off the soil, leave the tubers to dry for a few days and then store them cool (about 5 to 8 °C), dark and frost-free in dry sand or sawdust, without them touching; check occasionally for rot and plant them out again after the Ice Saints.
Propagation
Methods
- Division
- Cuttings
- From seed
Three methods are available to you, with tuber division and cuttings the most important for true-to-type propagation. Dahlias raised from seed do not come true.
Tuber division: Take the tubers out of winter quarters from the end of February to early March. Wait until small eyes can be seen sprouting at the crown (the stem base); only then can you tell for sure where new shoots will form. If the eyes are hard to spot, keep the tubers warm and bright for a few days until they show. Divide with a clean, sharp knife so that each piece carries at least one eye and a piece of the mother stem (crown neck); pieces without an eye stay “blind” and do not sprout. Shrivelled tubers can be soaked in cool water for an hour before dividing. Let the pieces establish straight away in moist, not wet, substrate.
Cuttings: From early February, lay the tubers half buried in soil, warm (16 to 18 °C) and bright, so that the shoot tips stay visible. When the shoots are 6 to 8 cm long and carry two to three pairs of leaves, cut them off just above the tuber. Pot them immediately in well-drained seed compost and keep the substrate evenly moist without waterlogging; regular airing prevents mould. From the end of March you can put the young plants outside by day to harden off, and plant them out in the bed after the Ice Saints (mid-May).
Sowing: From February to early April, sow the seeds only just 0.5 cm deep in seed compost, cover them and keep them moist at about 20 °C. Note: sowing suits only non-named dahlias (e.g. mixes) or new breeds. The dahlia is a natural hybrid and is cross-pollinated by insects, so seedling offspring flower differently in colour and form from the parent variety. Flowering is usually from August in the first year.
Companion planting
Companion planting is partly traditional gardening lore. Where the reason is known, it is given.
Some of these explanations were machine-translated.
For signed-in gardeners
Sign in to see symptoms, severity, season and prevention for every one of your plants.
Free account, set up in 30 seconds.
For your garden
Grow Dahlia yourself
Gartenkern tells you when frost is coming, when to sow and when to harvest, for your location.
Free, no time limit
Notes from real gardens
What other gardeners have written down about this variety, anonymous and voluntary.
No notes shared yet. Will you be the first to write one down?
From the magazine
Planting summer tubers in spring: dahlias and gladioli only after frost
Dahlias, gladioli and lilies go into the ground only after the last frosts. How to set summer tubers right and stake them from the start.
Overwintering dahlias and gladioli: dig up, dry, store
Dahlias and gladioli are not hardy. How to dig up the tubers in autumn, dry them properly, store them frost-free and divide them.