Sea Poppy, Horned Poppy, Yellow Horned Poppy
Glaucium flavum

Family: Papaveraceae (pa-pav-er-AY-see-ee) (Info)
Genus: Glaucium (GLAH-see-um) (Info)
Species: flavum (FLA-vum) (Info)
Synonym:Glaucium fulvum
Synonym:Glaucium luteum

Category:

Biennials

Perennials

Height:

18-24 in. (45-60 cm)

Spacing:

9-12 in. (22-30 cm)

Hardiness:

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)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

Sun Exposure:

Full Sun

Danger:

Parts of plant are poisonous if ingested

Bloom Color:

Orange

Bright Yellow

Bloom Time:

Late Spring/Early Summer

Mid Summer

Foliage:

Blue-Green

Other details:

Average Water Needs; Water regularly; do not overwater

Soil pH requirements:

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:

Non-patented

Propagation Methods:

From seed; direct sow outdoors in fall

From seed; direct sow after last frost

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds

Regional

This plant has been said to grow in the following regions:

,

Arroyo Grande, California

Calistoga, California

Clayton, California

Fairfield, California

Richmond, California

San Jose, California

Denver, Colorado

Sparks, Nevada

Hummelstown, Pennsylvania

show all

Gardeners' Notes:

4
positives
2
neutrals
0
negatives
RatingContent
Neutral

On Nov 17, 2014, coriaceous from ROSLINDALE, MA wrote:

In North America, this species has naturalized in 15 states and one province.

In my state, it is illegal to buy, sell, plant, or transport this species, because of the damage it does to natural areas (mostly shoreline).

Positive

On Mar 6, 2013, Domehomedee from Arroyo Grande, CA (Zone 9a) wrote:

What a good plant for dry areas. Mine was slow to start, probably because I bought it in a pot and transplanted it. However when it finally bloomed it was an attractive yellow flower. The seed pods are the kick though, very much like a California poppy seedpod, but these are humongous! A good 6" on my spindly first year transplant. Looking forward to more plants this spring.

Positive

On Jan 14, 2013, Denverdigger from Denver, CO wrote:

Horned poppies do very well in Denver, Colorado. We see shades of yellow, orange, and nearly-red. I can't imagine where it is "grown mainly for its foliage," as a previous post indicates. Last year I had a big display well into the hottest part of the summer (temps over 100 degrees), at which point the whole plant, including basal leaves, sort of retreated for a couple of weeks. We cut away the browned-out leaves and flower stalks, and soon had a whole new plant with a lush base and big display of blossoms. This lasted well into the cold weather. Usually, though, the plant just blooms all summer long. I deadhead as I can, but not very regularly. My current plant makes 2" seed pods, whereas my previous one made foot-long, curved pods "horns."

Positive

On Sep 19, 2008, slou from Hummelstown, PA wrote:

The right place for this plant: for me a very well drained, north facing slope, yields a great display. The substantial but brittle leaves are bright gray/white with a great rippled edges. The flowers are a poppy-like texture, clear orange in color. Very difficult to transplant, easily reseeds. Great addition. Looks striking with black mondo grass (Ophiopogon japonicus) - texture and color!

Positive

On Nov 12, 2002, poseygurl wrote:

Grown primarily for its foliage, yellow horned poppy is native to the British Isles, the Mediterranean and North Africa. It can be found growing wild near the sea and on shingle beaches above the high tide mark from the Mediterranean to southern Scandinavia. It has been grown in America as early as the 17th century. Thomas Jefferson planted it at Monticello in 1807. It grows 2-3 feet tall with deeply lobed gray-green leaves and 2-wide gold-yellow flowers. It gets its name from its long and narrow hornlike seed pods, which are popular for use in dried flower arrangements. Roots are poisonous and the plant has yellow sap. The plant contains glaucine, which lowers blood pressure and relieves coughs. The seeds yield an oil which has been used in lanterns. Glaucum flavum performs best in well-... read more

Neutral

On May 2, 2002, Lilith from Durham
United Kingdom (Zone 8a) wrote:

Also called the Yellow Horned Poppy, and a native of the UK, this is a striking plant of coastal dunes and shingle banks, with large yellow flowers held above blue-green foliage. Its curved, horn-like fruits, unlike those of the cornfield poppies, split open lengthways leaving the seeds embedded in a middle wall.