Eryngium agavifolium is a clump-forming member of the Apiaceae with deciduous foliage and a pronounced summer flowering period. It favours full sun and exposed positions on free-draining soils such as chalk, loam or sand. The plant tolerates a wide soil pH range and is classed H5 for UK hardiness. Use it where upright, architectural stems and reliable summer bloom are required.

Eryngium agavifolium thrives in full sun on well-drained chalk, loam or sand and flowers from June to September.

Eryngium is a genus of flowering plants in the family Apiaceae. There are about 250 species.

Eryngium agavifolium

Sea Holly | Eryngium agavifolium

Eryngium bromeliifolium is a clump-forming perennial in the Apiaceae with leathery, often spiny leaves that give it its common name. It flowers from June to September. Suited to sharply drained, neutral to alkaline soils on a south- or west-facing, exposed site.

Pineapple-leaved eryngo Eryngium bromeliifolium is a Mexico-native perennial for full sun and sharply drained gravel that flowers June to September.

Eryngiums are the sea hollies, grown for cone-shaped flowerheads set in a stiff ruff of spiny bracts, the whole structure frequently suffused with metallic blue or silver that extends down the stem. Foliage is leathery, often marbled or spined, and the seedheads dry to a sculptural skeleton that lasts through winter. The genus splits usefully into the drought-tolerant European species for hot dry gravel and the rosette-forming South American kinds with sword-like evergreen leaves.

Eryngium bromeliifolium

Pineapple-leaved eryngo | Eryngium bromeliifolium

Eryngium causcasicum is a species in the genus Eryngium, placed in the Apiaceae. It flowers in the UK from June to September. Specific appearance, size and cultivation needs vary by provenance and cultivar, so check supplier details before planting. Growers should confirm labelled recommendations for site and soil to match the plant's requirements.

Eryngium causcasicum flowers in the UK from June to September; check supplier details for provenance and cultivation guidance.

Eryngium causcasicum

Eryngium decaisneana is a clump-forming, upright perennial in the Apiaceae with leathery, often spiny foliage and a branching habit; some forms produce basal rosettes. It favours sharply drained, neutral to alkaline soils and thrives in full sun on a south- or west-facing, exposed site. Flowering occurs June to September. Avoid winter-wet positions, which this species does not tolerate.

Sea Holly (Eryngium decaisneana) is a clump-forming perennial that flowers June to September and suits sunny, sharply drained gravel or chalk soils.

Eryngium decaisneana

Sea Holly | Eryngium decaisneana

Eryngium eburneum is a flowering member of the Apiaceae genus Eryngium, notable for its structured umbels and spiny bracts characteristic of the genus. Plants in Eryngium commonly produce dome-shaped flowerheads and a distinctive architectural habit. The genus contains around 250 species with a wide, largely cosmopolitan distribution. In the UK it flowers from June to September.

Eryngium eburneum flowers in the UK from June to September and belongs to the Apiaceae genus Eryngium.

Eryngium eburneum

Eryngium floribundum is a clump-forming perennial in the Apiaceae, notable for leathery, often spiny leaves that may show silver veining. It grows upright and branching, with some plants forming a basal rosette. Flowering occurs June to September. It prefers exposed, south- or west-facing sites with sharply drained soil.

Sea Holly (Eryngium floribundum) is a Mexican perennial with spiny, leathery leaves that flowers June to September and suits dry, sharply drained sites.

Eryngium floribundum

Sea Holly | Eryngium floribundum

Eryngium horridum is a perennial sea holly with leathery, often spiny foliage and an upright, clump-forming habit. Plants produce branching stems or basal rosettes and the leaves are sometimes marbled or silver-veined. It is native to the coastal regions of southwestern Europe, notably Spain and Portugal. Flowering occurs from June to September.

Sea Holly (Eryngium horridum) is a clump-forming perennial for exposed, sharply drained gravel and coastal sites, flowering June to September.

Eryngium horridum

Sea Holly | Eryngium horridum

Eryngium planum 'Blaue Kappe' is an herbaceous perennial in the Apiaceae with branched silvery-blue stems carrying many small, conical blue flowerheads framed by spiky bracts. It typically reaches around 50 cm. Flowering runs from June to September, offering summer colour and architectural seedheads.

Blue Eryngo Eryngium planum 'Blaue Kappe' produces conical blue flowerheads set in spiky bracts from June to September.

Eryngium planum 'Blaue Kappe'

Blue Eryngo | Eryngium planum 'Blaue Kappe'

Eryngium planum 'Seven Seas' is a herbaceous perennial in the Apiaceae with thistle-like flowerheads composed of small blue cones surrounded by spiky bracts. Stems are branched and silvery-blue, carrying the flowerheads above a basal rosette. Flowering runs from June to September. The cultivar presents a compact habit, typically suited to mid-border or gravel planting.

Eryngium planum 'Seven Seas' bears blue conical flowerheads with spiky bracts and flowers from June to September.

Eryngium planum 'Seven Seas'

Blue Eryngo | Eryngium planum 'Seven Seas'

Eryngium proteiflorum is a perennial in the Apiaceae with protea-like flower heads and an upright, clump-forming, branching habit. Leaves are leathery and often spiny, sometimes marbled or silver-veined, with some plants forming basal rosettes. Native to Mexico, it flowers from June to September and demands full sun. Plant on sharply drained sand, chalk or gravel in a south- or west-facing, exposed position because winter wet is fatal.

Protea-like-flowered eryngo (Eryngium proteiflorum) flowers June to September and prefers full sun in sharply drained, neutral to alkaline soil.

Eryngium proteiflorum

Protea-like-flowered eryngo | Eryngium proteiflorum

Eryngium serra is a perennial in the Apiaceae with leathery, often spiny leaves and an upright, clump-forming, branching habit. It favours exposed, south- or west-facing positions and performs on poor to moderately fertile, sharply drained soils such as sand, chalk or gravel. Flowering occurs June to September. Plants may be deciduous or evergreen and sometimes show silver veining on the foliage.

Sea Holly (Eryngium serra) thrives in full sun on sharply drained, neutral to alkaline soils and flowers June to September.

Eryngium serra

Sea Holly | Eryngium serra

Eryngium tripartitum of gardens is a perennial in the Apiaceae with a clump-forming, upright and branching habit. It bears leathery, often spiny leaves that may be marbled or show silver veining. The plant favours full sun on sharply drained, neutral-to-alkaline soils and will not tolerate winter wet; it flowers from June to September.

Tripartite eryngo (Eryngium tripartitum of gardens) is a clump-forming perennial with leathery, often spiny leaves that prefers full sun and sharply.

Eryngium tripartitum of gardens

Tripartite eryngo | Eryngium tripartitum of gardens

Eryngium variifolium is a perennial from Morocco with a clump-forming, upright and branching habit and often spiny, leathery leaves. Foliage can be deciduous or evergreen and is sometimes marbled or silver-veined. It flowers from June to September and suits sharply drained, sunny sites.

Variable-leaved eryngo (Eryngium variifolium) is a Moroccan perennial with spiny, leathery leaves and June to September flowers, suited to sharply drained.

Eryngium variifolium

Variable-leaved eryngo | Eryngium variifolium

Eryngium x zabelii 'Big Blue' is a clump-forming, deciduous member of the Apiaceae valued for its summer flowering. It blooms from June to September. Plant it in full sun on well-drained chalk, loam or sand and place where east, west or south aspects receive direct light. Tolerant of exposed sites and hardy in most UK gardens (H5).

Eryngium x zabelii 'Big Blue' flowers from June to September and prefers full sun on well-drained chalk, loam or sand.

Eryngium x zabelii 'Big Blue'

Sea Holly | Eryngium x zabelii 'Big Blue'

Eryngium × oliverianum is a clump-forming perennial in the Apiaceae with upright, branching stems and leathery, often spiny leaves. Some selections form basal rosettes and foliage may be marbled or silver-veined. It favours full sun on sharply drained sand, chalk or gravel and will not tolerate winter wet. Flowers appear from June to September.

Sea Holly (Eryngium × oliverianum) suits south- or west-facing sharply drained gravel or chalk and flowers from June to September.

Eryngium × oliverianum

Sea Holly | Eryngium × oliverianum

Eryngium × zabelii is a clump-forming perennial in the Apiaceae with upright, branching stems and often spiny, leathery foliage. It flowers from June to September and is suited to sharply drained soils. Plant it in full sun on a south- or west-facing, exposed site where winter wet is avoided.

Sea Holly (Eryngium × zabelii) suits sunny, south- or west-facing gravel and border sites and flowers June to September.