Echinops ritro Seeds | Small Globe Thistle
LATIN NAME: Echinops ritro
COMMON NAME: Small Globe Thistle
Plant Profile
Small globe thistle is an upright, clump-forming herbaceous perennial of the daisy family, and the height usually given for it needs correcting: it grows sixty to ninety centimetres tall, occasionally a metre, not the five to ten metres that some databases carry over from tree records. The stems are stout, white-woolly and sparingly branched, and they rise from a deep taproot that makes the plant drought-proof and difficult to move.
The leaves are the plant’s other weapon. They are deeply cut, dark green above and white-felted beneath, and each lobe ends in a sharp spine, so that a clump is genuinely unpleasant to handle without gloves. The foliage forms a low rosette in spring and then climbs the stem in decreasing size, giving the plant a architectural, almost sculptural outline before a single flower opens.
The flower heads are the reason it is grown. Each one is a sphere of tiny florets, three to four centimetres across, steel-blue to grey-blue, held on its own short stalk above the foliage. They open from the top of the sphere downward over several weeks in midsummer, and they dry on the plant into a brown, prickly ball that holds its shape into winter.
Its native range covers southern and central Europe, the Mediterranean and western Asia, on dry, stony, calcareous grassland, road verges and rocky slopes. It is a plant of poor ground and full sun, and it becomes loose and floppy in rich soil or shade.
Science & Biotechnology
The globe head is a compound inflorescence, and its structure is a defence as well as a display. Each sphere contains dozens of small florets packed together, and each floret is a tube that opens at the top into five narrow lobes. The sphere shape means that a bee landing on it can walk over many florets in one visit, which makes the plant an efficient nectar source, and it also means that the developing seed is protected inside a prickly cage.
The genus is placed in the Cardueae, the thistle tribe, and it is unusual within that group for its unisexual florets, with male and female flowers on the same head or on different heads depending on the species. Echinops ritro is gynodioecious in some populations, with female plants bearing smaller heads and male plants bearing larger ones, which is one reason the flower colour and size vary between plants in a batch.
The chemistry of the genus has been studied mainly in Echinops sphaerocephalus and in the medicinal species, where alkaloids, thiophenes and sesquiterpene lactones have been identified. Extracts have shown antimicrobial and anti-inflammatory activity in vitro, and some of the thiophenes are phototoxic, which is a genuine hazard for anyone handling the sap in strong sunlight.
The seed is a cypsela with a deciduous pappus, dispersed by wind over short distances and by animals on fur. Germination is straightforward, without a dormancy requirement, which is why the plant self-sows readily in a gravel garden and why it can become a nuisance in a small border.
Uses & Benefits
In the garden it is a plant for a dry border, a gravel garden or a wildflower meadow, where its steel-blue heads and spiny foliage can be seen against grasses and silver-leaved plants. It is excellent with lavender, with cistus and with the ornamental grasses, and it holds its shape through the summer without staking. The dried heads are useful in winter arrangements and are long-lasting in a vase.
The flowers are a strong bee and butterfly plant, and the globe shape is accessible to short-tongued insects as well as long-tongued ones, which makes it more useful than many daisies. It is also a good cut flower, both fresh and dried, and the dried heads are sold by florists for their form and colour.
The plant has a modest medicinal history in European and Asian folk practice, where the root and the flower heads were used for headaches, for digestive complaints and as a diuretic. There is no clinical evidence, and the thiophenes in the sap are phototoxic, so handling the plant on a sunny day can cause a rash. It should be treated as an ornamental, not a remedy.
Ecologically it is a useful plant for a wild garden, since it feeds a wide range of insects and its seed is eaten by goldfinches in autumn. It is also a good plant for a poor, dry site where little else will grow, and it tolerates lime, drought and neglect without complaint.
Growing from Seed
Sow the seed in spring, on the surface of a gritty, free-draining mix, and cover it lightly. Keep at eighteen to twenty-two degrees in bright light, and expect germination in two to four weeks. The seed is large and easy to handle, and fresh seed germinates reliably without any pre-treatment.
Grow the seedlings on in full sun, in a free-draining mix, and plant them out once the root has filled the pot, into a poor, stony soil. Do not enrich the ground, since rich soil produces tall, floppy growth that needs staking; a handful of grit and a sunny site are better than compost. The plant self-sows freely once established, and seedlings can be lifted and moved in spring if they appear where they are not wanted.
Our Take
Small globe thistle is one of the most reliable blue flowers for a dry garden, and one of the few that looks good after it has finished flowering. It is spiny, it self-sows, and it resents being moved, but none of that matters against the fact that it will flower in August on a bank where nothing has been watered all summer.
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