Silybum marianum
Milk thistle
At a glance
- Light
- Full sun
- Spacing
- 40 cm, rows 50 cm
- Lifespan
- Biennial
- Sowing
- Apr–May
- Harvest
- Jul–Sep
- Hardiness
- Cold damage below −5 °C
- Water need
- Low
Photo: C T Johansson · CC BY 3.0 · Source
This description was machine-translated.
Description
The milk thistle, botanically Silybum marianum, is easy to recognise by its glossy green, white-marbled leaves and its striking purple thistle flowers, which appear from July. It originates in the Mediterranean region but copes well with sunny, dry sites in gardens. Its sharply toothed leaves carry fine spines, so it is best to handle it with gloves. The spines can prick unpleasantly, so a spot away from a children's bed is worthwhile.
Care instructions
Choose a full-sun, warm site with permeable, rather lean soil, as milk thistle tolerates waterlogged conditions poorly. Sow directly outdoors from mid April to May. As a taproot plant, it forms a deep root early and can hardly be transplanted later. Water sparingly once the young plants have established, as they cope with longer dry periods. Keep the bed free of weeds for the first few weeks, after which milk thistle holds its own against competition thanks to its spiny foliage. Harvest the flower heads as they open, preferably with sturdy gloves because of the spines.
The care notes were machine-translated from German.
Garden year
SowingApr–May
HarvestJul–Sep
Germination
- Soil temperature
- from 10 °C, ideally 20 °C
- Days to sprout
- 10 to 21 days
- Light
- Sprouts in light or dark
- Sowing depth
- 1.5 cm
- How to start
- Sow straight into the bed
Soil & site
Soil pH
Soil type
well-drained, lean, lime-loving, dry
Milk thistle comes from dry Mediterranean sites and accordingly wants it lean. A well-drained, rather lean soil with some lime suits it best; it tolerates heavy and waterlogged soils badly. A sunny spot at a wall or on a gravel bed suits its roots very well.
Feeding
Light feeder
As an undemanding wild plant, milk thistle needs practically no feeding. Soil that is too rich makes it quickly run to leaf instead of setting strong seeds. A thin helping of compost at planting is entirely enough; after that you can simply let it grow.
Overwintering
In the first year milk thistle forms only a leaf rosette, which is hardy and gets through without protection. Only in the second year does it send up the flower stalk and then sets seed. In mild winters a mulch layer of leaves around the rosette is enough; in very exposed locations you protect the root additionally with some brushwood.
Propagation
Methods
- From seed
Propagation works exclusively from seed, which you sow directly in the bed in spring from April. Milk thistle is a light germinator, so only press the seeds in lightly instead of covering them. At 15 to 20 degrees it germinates reliably within two to three weeks. Since it forms a taproot, it tolerates transplanting badly, so raise it directly at its final location.
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 Milk thistle 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?