PerennialsEryngium planum
Sea Holly
Sea Holly is a striking perennial with steel-blue, thistle-like flower heads on branching stems. Blooming in July and August, it adds unique texture and colour to sunny borders. Excellent as a dried flower and a magnet for pollinators.
Characteristics
- Sun
- Full sun
- Water
- Low
- Height
- 50–80 cm
- Spread
- 30–45 cm
- Hardiness zone
- 5–9
- Family
- Apiaceae
- Evergreen
- No
- Flower colors
- blue
- Wildlife value
- bees, butterflies, hoverflies
Bloom period
Care guide
Plant in full sun in poor, well-drained soil. Sea Holly thrives in lean, dry conditions and needs no fertiliser. Too-rich soil produces floppy growth. Once established, the plant requires virtually no maintenance.
Pruning tips
Leave flower heads standing into autumn for structure and to feed birds. Cut stems back to ground level in late autumn or early spring. The flower heads also make superb dried flowers — cut them at peak bloom for drying.
Good companions
PerennialsAchillea millefolium
Yarrow
Yarrow is a robust native perennial with finely divided, fern-like foliage and flat flower clusters in yellow, white, or pink. The plant blooms prolifically from June to September, attracting countless pollinators. Yarrow is remarkably drought-resistant and fits almost any garden style, from prairie borders to wildflower meadows.
PerennialsPerovskia atriplicifolia
Russian Sage
Russian Sage is a graceful sub-shrub with silvery-grey aromatic foliage and airy lavender-blue flower plumes from July to September. The plant can reach 150 cm and gives borders a hazy, ethereal quality. Russian Sage is highly drought-tolerant and thrives on poor, dry soil.
PerennialsSalvia nemorosa
Woodland Sage
Woodland Sage is a compact perennial with striking purple-blue flower spikes blooming from June to August. It attracts plenty of bees and butterflies and works well in sunny borders. Cutting back spent flower stems often triggers a second flush of blooms.