Eryngium Species, Sea Holly

Eryngium planum

Family: Apiaceae (ay-pee-AY-see-ee) (Info)
Genus: Eryngium (er-RIN-jee-um) (Info)
Species: planum (PLAN-um) (Info)
Synonym:Eryngium armatum
Synonym:Eryngium caeruleum
Synonym:Eryngium intermedium
Synonym:Eryngium latifolium
Synonym:Eryngium planifolium
View this plant in a garden



Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun


Grown for foliage

Foliage Color:



36-48 in. (90-120 cm)


18-24 in. (45-60 cm)


USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

Where to Grow:

Grow outdoors year-round in hardiness zone


Unknown - Tell us

Bloom Color:


Bloom Characteristics:

Flowers are good for cutting

This plant is attractive to bees, butterflies and/or birds

Flowers are showy

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Late Summer/Early Fall

Other details:

Unknown - Tell us

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:


Propagation Methods:

By dividing the rootball

From herbaceous stem cuttings

From woody stem cuttings

From softwood cuttings

From semi-hardwood cuttings

From seed; direct sow outdoors in fall

From seed; winter sow in vented containers, coldframe or unheated greenhouse

From seed; stratify if sowing indoors

Seed Collecting:

Allow pods to dry on plant; break open to collect seeds

Allow seedheads to dry on plants; remove and collect seeds

Properly cleaned, seed can be successfully stored


This plant is said to grow outdoors in the following regions:

Lincoln, (258 reports)

Prattville, Alabama

Vincent, Alabama

Little Rock, Arkansas

Claremont, California

Hesperia, California

Menifee, California

Silverado, California

Colorado Springs, Colorado

Denver, Colorado

Fort Collins, Colorado

Carrollton, Georgia

Saint Charles, Illinois

Washington, Illinois

Greenville, Indiana

Bloomfield, Iowa

Springfield, Massachusetts

Bellaire, Michigan

Hastings, Michigan

Ludington, Michigan

Deer River, Minnesota

Minneapolis, Minnesota(2 reports)

Saint Paul, Minnesota

Wrightstown, New Jersey

El Prado, New Mexico

Buffalo, New York(2 reports)

Ithaca, New York

Belfield, North Dakota

Defiance, Ohio

Lancaster, Pennsylvania

Conway, South Carolina

Abilene, Texas

Alleyton, Texas

Georgetown, Texas

Alexandria, Virginia

Leesburg, Virginia

Kalama, Washington

Seattle, Washington

Spokane, Washington

show all

Gardeners' Notes:


On Aug 6, 2015, klinc1234 from Little Rock, AR (Zone 7b) wrote:

I planted several of these and they bloom but the foliage has not performed well - so I'm wondering if anyone growing these plants in the South can offer suggestions. My plants appear to perform better in spring and fall (so I'm wondering if they would benefit from some shade in 7b). Also the soil they are in now drains well (but I could try them someplace with even sandier soil in my yard).
Does anyone have experience growing these and Eryngium yuccifolium? How much can they be treated the same?


On Jun 4, 2015, Janeathan from Fort Collins, CO wrote:

I put this on parkway corner that gets hot afternoon winds in semi sun/shade, and lots of dogs peeing on it. It is doing great. Dense foliage at base crowds out other weeds, the dogs can't dig or bust it up. A bit leggy & needs staking, plus it has gotten quite tall, so I want to move it further back in the bed with more room & sun. They do readily seed and move around in your bed, so a spot with wiggle room is best.


On Jun 21, 2014, quasymoto from Bloomfield, IA (Zone 5b) wrote:

I have had this plant for Several years and I don't know why I planted it with Red Carpet Border lilies, but I did. And now I am thinking I need t dig it out of there as it is getting crowded out. I hope to report back soon that it was successful. I also have one growing under a Chinese spice bush that I may dig out as well, Or do you think I should wait til the other one is dug out and gets Established?


On Apr 2, 2010, Spiderfrog from Stoney Creek Ont.,
Canada wrote:

This plant is interesting and happy to have added to my border but it does sprawl and requires stakes to keep its form. I added sand and some gravel to the base and it performed well. Now that it's taller than planned I'll carefully move it to the back


On Aug 11, 2007, Gabrielle from (Zone 5a) wrote:

This is growing in a poor, somewhat shady area in my yard. Flowers are very interesting; almost look spraypainted!

Blooms June - July in my garden.


On Feb 18, 2006, MattiN from Nurmijrvi,
Finland wrote:

I beliewe that this plant has been grown in Finland for decades if not over a century, it is even too weedy in zone 4, propably even 3. But it is unusual (despite being so common), and removing the seedheads is really not a big trouble - and they make nice cutflowers even at late age. You just have to remember to cut them off, othervise your rockery will be run over by them. I grow it with my grasses, and so far I have left a few blooms to set seed to give the single plant a change to make a few daughters. This species is perhaps underestimated, as it lacks the beuty of some of the other eryngiums. I like the leaves, too.


On Jul 6, 2005, Joan from Belfield, ND (Zone 4a) wrote:

Add another zone 4 survival here. I know it's rated zone 5, but it seems to be holding it's own in zone 4.


On Nov 9, 2004, lmelling from Ithaca, NY (Zone 5b) wrote:

I grow the cultivar "Blaukappe" (Blue Cap), which gives steel tiny silver-blue flowers arranged in round clusters. After flowering the heads become a steel blue and can be cut and dried for use in arrangements. My plants here in zone 5 generally grow to about 2.5' and branch nicely. Looks pretty and contrasts nicely next to lambs ears.

Eryngium has an extremely long taproot and so it is hard to move a larger plant. I have had success with moving smaller "babies" which have self seeded close by. You must dig down quite far and remove as much as the taproot as possible - pot or plant immediately. I have had success in giving away several of the babies - or moving to new locations in this manner. Best to move in early spring. Foliage is a nice deep green and grows clos... read more


On Jun 20, 2003, tervito from Minneapolis, MN wrote:

I want to add a note of interest on this plant. Despite a harsh zone 4 winter in Minnesota (-20F and below with no snow until the end of summer) and their being entirely unprotected an on an exposed boulevard, the nine plants that successfully took from seed last year (no bloom of course) have returned and are now starting to bloom. I didn't notice the Zone 5 specification on the seed packet until this year!

Go figure, I have supposedly hardy plants that just up and died despite all manner of pampering, and these babies defy all odds to return.

I have them planted with yarrow, quaking grass, Bells of Ireland, moss roses, and sedum. Looks pretty good.


On Aug 31, 2001, smiln32 from Oklahoma City, OK (Zone 7a) wrote:

Easily grown in dry, sandy, well-drained soils in full sun. Tolerates poor soils. Self-seeds in optimum growing conditions. Tall plants tend to sprawl, particularly if grown in overly fertile soils or in anything less than full sun. This is a taprooted plant which transplants poorly and is best left undisturbed once established.