Centaurea montana
Mountain Bluet
Common names: Perennial Mountain Cornflower, Mountain Cornflower
At a glance
- Light
- Full sun
- Pot size
- from 10 l
- Lifespan
- Perennial
- Flowering
- May–Jul
- Hardiness
- Hardy down to −30 °C
- Water need
- Medium
- Origin
- Native to Germany
Photo: User:Stemonitis · CC BY-SA 2.5 · Source
This description was machine-translated.
Description
The mountain cornflower, botanically Centaurea montana, comes from mountain woodlands and mountain meadows in the mountain ranges of Central and Southern Europe and has long been a classic of the cottage garden. It forms loose clumps with grey-green, lanceolate leaves and blooms from May to July on stems 30 to 60 cm tall. The large, cornflower-like flower heads are blue on the outside with narrow, deeply cut marginal florets and purple-violet on the inside. Wild bees, bumblebees and butterflies visit it readily. In the bed it pairs well with roses, cranesbill and grasses, and it also suits the edge of woody plantings and containers. It spreads by short runners and by seed, so plan for some space or cut off the seed heads if you want to limit it.
Care instructions
Plant the mountain cornflower in spring or autumn in a sunny to partly shaded spot with well-drained soil, keeping about 40 cm between plants. Water regularly in the first year and later only during prolonged dry periods. Fertilizer is rarely needed. After the main flowering in June or July, cut the plant back to about 10 cm above the ground. It regrows fresh and often flowers again in August or September, and it self-seeds less. Remove old shoots in early spring. Divide the clump every 2 to 3 years, otherwise it declines in the centre. If mildew appears on the leaves, ensure good air circulation and cut out affected shoots. Typical mistakes are waterlogging and planting too closely.
The care notes were machine-translated from German.
Garden year
SowingApr–Jun
FloweringMay–Jul
Germination
- Soil temperature
- from 10 °C, ideally 18 °C
- Days to sprout
- 10 to 21 days
- Light
- Needs darkness to sprout
- Sowing depth
- 0.5 cm
- How to start
- Sow straight into the bed
Soil & site
Soil pH
Soil type
well-drained, humus-rich, loamy
The mountain cornflower is undemanding and grows in any well-drained, humus-rich garden soil, most beautifully in loamy, fresh to moderately dry soil with a neutral to slightly chalky reaction. It tolerates sun and light partial shade. It does not like waterlogging, especially in winter; on heavy soil, mix in sand or compost. In very nutrient-rich soil the shoots become long and soft and flop apart after rain.
Feeding
Light feeder
The mountain cornflower usually gets by without fertiliser. On very poor, sandy soil you can work in some mature compost in spring; it needs nothing more. Too many nutrients make the shoots soft, so that they flop apart after rain, and reduce flowering. In a container, replace the top layer of soil with fresh soil each spring.
Overwintering
The mountain cornflower is completely hardy and needs no protection in the bed. Cut off the old shoots in late autumn or in early spring. In a container, put the pot against a sheltered house wall, raise it on feet and wrap it in horticultural fleece or hessian in hard frost so that the root ball does not freeze through.
Propagation
Methods
- From seed
- Division
The easiest way is to divide older plants: in spring or autumn, dig up the rootstock, divide it with a spade into pieces with several shoots and replant them straight away. Every 2 to 3 years this rejuvenates the stand. Sowing works too: from April to June, scatter the seeds on loose soil and cover them only thinly with soil. Plants raised from seed usually flower only in the second year. Over time the plant sows itself and spreads by short runners.
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 Mountain Bluet yourself
Gartenkern tells you when frost is coming, when to sow and when to harvest, for your location.
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