When to plant
Plant Eryngium bare-root plants in spring once the soil has warmed. This gives the roots time to establish before the heat of summer. In mild climates, late autumn planting is also possible.
Where to plant
Choose a position in full sun — Eryngium needs strong sunlight to develop its best colour. Ideal locations include gravel gardens, dry borders, coastal sites and any well-drained, exposed area. Avoid shade or damp soil, as plants may weaken or rot.
Preparing the soil
Loosen soil to 20–25 cm and ensure it drains freely. Eryngium thrives in poor or moderately fertile soil and dislikes rich, heavy, or waterlogged ground. Improve clay with plenty of grit or coarse sand. Do not over-enrich the soil with compost — lean soil produces stronger, more colourful plants.
Preparing the bare-roots
Soak the bare-root plants in lukewarm water for 30–60 minutes before planting to hydrate them fully. Handle gently to avoid damaging the developing crown and taproot.
Planting the bare-roots
Plant the crown at soil level, with the top of the crown just covered. Space plants 40–50 cm apart to allow the rosette and flowering stems to develop properly. Eryngium develops a deep taproot — once planted, it prefers not to be moved.
After planting
Water in well, then allow the soil to dry slightly between waterings. Overwatering is the most common cause of failure. Mulching is not necessary and can trap moisture around the crown — best avoided.
During growth
Eryngium thrives in heat and dry conditions. Water only during prolonged drought. Deadhead the first flush of flowers if you want a second flowering, or leave seed heads in place for autumn structure and wildlife interest.
After flowering
Cut back old stems in late autumn or early spring. If left over winter, the seed heads provide excellent structure and are attractive to birds. Do not divide the plant — Eryngium dislikes disturbance due to its taproot.
Extra tips
Eryngium is ideal for hot, dry, coastal or low-maintenance gardens. The flowers are excellent for both fresh and dried arrangements. To ensure strong colour and sturdy stems, always provide full sun and very well-drained soil.
