Cosmos bipinnatus
Cosmos
Common names: Cosmos daisy, Cosmos flower
At a glance
- Light
- Full sun
- Pot size
- from 15 l
- Lifespan
- Annual
- Hardiness
- Cold damage below 0 °C
- Water need
- Low
- For children
- Well suited
Photo: Hugo.arg · CC BY-SA 3.0 · Source
This description was machine-translated.
Description
The ornamental little basket blooms from July until the first frost with delicate, shell-shaped flowers in white, pink, and carmine red over finely feathery, fern-like foliage. The airy perennials grow up to 120 cm tall, sway in the wind, and provide a lush buffet for butterflies, bees, and hoverflies. As a cut flower, it brings playful lightness to any bouquet.
Care instructions
Sow it from the end of April directly into the garden bed in full sun; it germinates quickly and prefers lean soils, because in overly rich soil the foliage grows at the expense of flowers. Water only during prolonged dry periods. Regularly remove spent flowers, then it will continue to bloom relentlessly. Tall varieties benefit from a light support in windy locations.
The care notes were machine-translated from German.
Garden year
SowingApr–May
Germination
- Soil temperature
- from 12 °C, ideally 20 °C
- Days to sprout
- 5 to 10 days
- Light
- Sprouts in light or dark
- Sowing depth
- 0.5 cm
- How to start
- Start indoors, then plant out
Soil & site
Soil pH
Soil type
sandy, well-drained, lean, humus-rich
Plant the garden cosmos in free-draining, rather poor to moderately nutrient-rich soil. Sandy or sandy-loamy soil is ideal. You must avoid waterlogging at all costs, and soil that is too rich only produces foliage at the expense of flowers.
Feeding
Light feeder
Months
Mar–Apr
In spring before sowing, work a thin layer of mature compost shallowly into the soil. Nothing more is needed. On well-supplied garden soil you can leave out feeding entirely, because too much nitrogen noticeably slows flowering.
Overwintering
The garden cosmos is an annual and dies with the first frost. There is nothing to dig up or bring indoors. In autumn, leave a few seed heads standing and the cosmos will seed itself; alternatively, harvest the ripe, dark brown seeds dry and store them cool and dry until sowing next spring.
Propagation
Methods
- From seed
The garden cosmos is an annual summer flower and is propagated exclusively by sowing. Cuttings, division or layering are not practical. The plant germinates so quickly and reliably that vegetative methods are unnecessary.
Starting indoors (recommended): Sow the seeds from mid-March in seed trays with loose seed compost. The garden cosmos needs light to germinate. So cover the seeds only very thinly (at most 0.5 cm) or just press them in lightly, and keep the substrate evenly moist. At 18 to 22 °C the seeds germinate after about one to three weeks. As soon as the seedlings have two pairs of leaves, prick them out individually into small pots. From mid-May, after the Ice Saints, plant the young plants outdoors with a spacing of 35 to 40 cm.
Direct sowing: Sow directly in the bed from late April to mid-May, as soon as the soil is frost-free and somewhat warmed. Scatter the seeds shallowly and cover them only lightly (they need light to germinate), then press them in. Germination after about two to four weeks.
Using self-seeding: If you let individual plants set seed at the end of the season, Cosmos bipinnatus reliably seeds itself. The seeds are frost-hardy and overwinter in the soil; the seedlings appear by themselves in spring. For true-to-type offspring, collect the ripe seeds and store them cool, dry and dark until the next sowing.
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 your garden
Grow Cosmos yourself
Gartenkern tells you when frost is coming, when to sow and when to harvest, for your location.
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