How to Grow Sea Hollies USA

By the SoilCommander Editorial Team, under the guidance of Nitin Sharma, Co-Founder · · How we check our facts

On this page
  1. Sea Holly (Eryngium maritimum)
  2. Soil & Growing Conditions
  3. Growth Stages
  4. Quick Facts
  5. At a Glance
  6. Harvest & Storage
  7. Diseases
  8. Pests
  9. Plan your Sea Hollies planting
  10. Growing Sea Holly in another region
  11. Sources
  12. Frequently Asked Questions

Sea holly (Eryngium maritimum) — herbaceous perennial.

Unlike an annual crop, the work here is front-loaded into establishment: get the planting and the site right and the same plants crop for several seasons.

Core growing advice on this page is checked against named horticultural sources — see References.

Sea Holly (Eryngium maritimum)

Close-up of sea holly's blue globular flower umbel with spiny bracts — “Eryngium maritimum 148703044” by Marcel Hospers is licensed under CC BY-SA 4.0.

3 sources cited · Verified

Soil & Growing Conditions

A clump of sea holly growing among dune grasses — “Sea Holly (Eryngium maritimum)” by JarroNevsbaru is licensed under CC BY-SA 4.0.
“Sea Holly (Eryngium maritimum)” by JarroNevsbaru is licensed under CC BY-SA 4.0.

Water: tolerates drought once established, well-drained (RHS)

Growth Stages

Close-up of a sea holly leaf with a snail — “Eryngium maritimum - Sea Holly - Kum Boğadikeni 01” by Zeynel Cebeci is licensed under CC BY-SA 4.0.
“Eryngium maritimum - Sea Holly - Kum Boğadikeni 01” by Zeynel Cebeci is licensed under CC BY-SA 4.0.
Stage BBCH Notes
Sowing 0 Propagate by seed in autumn, into sandy, free-draining soil in full sun (RHS).
Clump establishment 3 Forms a clump of waxy, stiff, spiny blue-green foliage; takes 2-5 years to reach full maturity (RHS).
Flowering 6 Globular blue flower umbels, surrounded by spiky bracts, appear April to September (RHS).
Root and shoot harvest 8 Young shoots blanched and harvested as an asparagus substitute; roots dug and cooked or candied (The Backyard Larder).

Quick Facts

Close-up of sea holly's blue globular flower umbel with spiny bracts — “Eryngium maritimum 148703044” by Marcel Hospers is licensed under CC BY-SA 4.0.
“Eryngium maritimum 148703044” by Marcel Hospers is licensed under CC BY-SA 4.0.
Factor Value
Soil texture sandy, free-draining, naturally occurs in coastal sand dunes and shingle (RHS)
Drainage well-drained
Lifecycle herbaceous perennial
Edible parts root, young shoots

At a Glance

A sea holly plant growing on a shingle beach — “Eryngium maritimum, Vic-la-Gardiole 02” by Christian Ferrer is licensed under CC BY-SA 4.0.
“Eryngium maritimum, Vic-la-Gardiole 02” by Christian Ferrer is licensed under CC BY-SA 4.0.
Eryngium maritimum Sea Holly Root rot (sea holly, ca… Powdery mildew Leaf and bud eelworms Snails Slugs DISEASES PESTS

Harvest & Storage

Sea holly's blue-green spiny foliage growing in sand — “Eryngium maritimum - Sea Holly - Kum Boğadikeni 03” by Zeynel Cebeci is licensed under CC BY-SA 4.0.
“Eryngium maritimum - Sea Holly - Kum Boğadikeni 03” by Zeynel Cebeci is licensed under CC BY-SA 4.0.

When to pick: Young shoots are cooked, blanched by excluding light from the growing plant, then used as an asparagus substitute. The root can be cooked as a vegetable or candied as a sweetmeat -- slightly sweet, tasting of carrot, and resembling parsnip or chestnut when roasted (The Backyard Larder).

Diseases

Close-up of sea holly's blue globular flower umbel with spiny bracts — “Eryngium maritimum 148703044” by Marcel Hospers is licensed under CC BY-SA 4.0.
“Eryngium maritimum 148703044” by Marcel Hospers is licensed under CC BY-SA 4.0.
Root rot (sea holly, causal agent not yet confirmed)
moderate

RHS names this directly: prone to root rot.

moderate

RHS names this directly: prone to powdery mildews.

Pests

A clump of sea holly growing among dune grasses — “Sea Holly (Eryngium maritimum)” by JarroNevsbaru is licensed under CC BY-SA 4.0.
“Sea Holly (Eryngium maritimum)” by JarroNevsbaru is licensed under CC BY-SA 4.0.
Leaf and bud eelworms
moderate

Aphelenchoides spp.

RHS names this directly: susceptible to leaf and bud eelworms.

Snails
low

Gastropoda (snails, various spp.)

RHS names this directly: susceptible to snails.

Slugs
low

Gastropoda (slugs, various spp.)

RHS names this directly: susceptible to slugs.

Plan your Sea Hollies planting

When to sow and plant Sea Hollies depends on your own frost dates. Check the USA vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Sea Holly in another region

Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.

Sources

The full list of 3 sources behind this guide (Plants For A Future (PFAF), Royal Horticultural Society, The Backyard Larder) is in the references of our UK guide to sea holly; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

What problems affect sea holly?

Our data links 2 diseases and 3 pests to this crop. See the sections above for each one and how to manage it.

Plan next season before the problems start

Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.

Get the USA Garden Planner →

Instant PDF download · Written for US growing conditions

SoilCommander Editorial Team — under the guidance of Nitin Sharma, Co-Founder

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing. How we check our facts.

How this guide is put together

The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against USDA hardiness-zone and frost-date data, with Cooperative Extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.

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Last verified 2026-09-02

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